@types/yargs

property argv

argv:
    | {
          [key in keyof Arguments<T> as
              | key
              | CamelCaseKey<key>]: Arguments<T>[key];
      }
    | Promise<{
          [key in keyof Arguments<T> as
              | key
              | CamelCaseKey<key>]: Arguments<T>[key];
      }>;

• Get the arguments as a plain old object.

  Arguments without a corresponding flag show up in the argv._ array.

  The script name or node command is available at argv.$0 similarly to how $0 works in bash or perl.

  If yargs is executed in an environment that embeds node and there's no script name (e.g. Electron or nw.js), it will ignore the first parameter since it expects it to be the script name. In order to override this behavior, use .parse(process.argv.slice(1)) instead of .argv and the first parameter won't be ignored.

property parsed

parsed: DetailedArguments | false;

• If the arguments have not been parsed, this property is false.

  If the arguments have been parsed, this contain detailed parsed arguments.

method alias

alias: {
    <K1 extends keyof T, K2 extends string>(
        shortName: K1,
        longName: K2 | readonly K2[]
    ): Argv<T & { [key in K2]: T[K1] }>;
    <K1 extends keyof T, K2 extends string>(
        shortName: K2,
        longName: K1 | readonly K1[]
    ): Argv<T & { [key in K2]: T[K1] }>;
    (
        shortName: string | readonly string[],
        longName: string | readonly string[]
    ): Argv<T>;
    (aliases: { [shortName: string]: string | readonly string[] }): Argv<T>;
};

• Set key names as equivalent such that updates to a key will propagate to aliases and vice-versa.

  Optionally .alias() can take an object that maps keys to aliases. Each key of this object should be the canonical version of the option, and each value should be a string or an array of strings.

method array

array: {
    <K extends keyof T>(key: K | readonly K[]): Argv<
        Omit<T, K> & { [key in K]: ToArray<T[key]> }
    >;
    <K extends string>(key: K | readonly K[]): Argv<
        T & { [key in K]: (string | number)[] }
    >;
};

• Tell the parser to interpret key as an array. If .array('foo') is set, --foo foo bar will be parsed as ['foo', 'bar'] rather than as 'foo'. Also, if you use the option multiple times all the values will be flattened in one array so --foo foo --foo bar will be parsed as ['foo', 'bar']

  When the option is used with a positional, use -- to tell yargs to stop adding values to the array.

method boolean

boolean: {
    <K extends keyof T>(key: K | readonly K[]): Argv<
        Omit<T, K> & { [key in K]: boolean }
    >;
    <K extends string>(key: K | readonly K[]): Argv<T & { [key in K]: boolean }>;
};

• Interpret key as a boolean. If a non-flag option follows key in process.argv, that string won't get set as the value of key.

  key will default to false, unless a default(key, undefined) is explicitly set.

  If key is an array, interpret all the elements as booleans.

method check

check: (
    func: (argv: Arguments<T>, aliases: { [alias: string]: string }) => any,
    global?: boolean
) => Argv<T>;

• Check that certain conditions are met in the provided arguments.

  Parameter func

  Called with two arguments, the parsed argv hash and an array of options and their aliases. If func throws or returns a non-truthy value, show the thrown error, usage information, and exit.

  Parameter global

  Indicates whether check() should be enabled both at the top-level and for each sub-command.

method choices

choices: {
    <K extends keyof T, C extends readonly any[]>(key: K, values: C): Argv<
        Omit<T, K> & { [key in K]: C[number] }
    >;
    <K extends string, C extends readonly any[]>(key: K, values: C): Argv<
        T & { [key in K]: C[number] }
    >;
    <C extends { [key: string]: readonly any[] }>(choices: C): Argv<
        Omit<T, keyof C> & { [key in keyof C]: C[key][number] }
    >;
};

• Limit valid values for key to a predefined set of choices, given as an array or as an individual value. If this method is called multiple times, all enumerated values will be merged together. Choices are generally strings or numbers, and value matching is case-sensitive.

  Optionally .choices() can take an object that maps multiple keys to their choices.

  Choices can also be specified as choices in the object given to option().

method coerce

coerce: {
    <K extends keyof T, V>(key: K | readonly K[], func: (arg: any) => V): Argv<
        Omit<T, K> & { [key in K]: V }
    >;
    <K extends string, V>(key: K | readonly K[], func: (arg: any) => V): Argv<
        T & { [key in K]: V }
    >;
    <O extends { [key: string]: (arg: any) => any }>(opts: O): Argv<
        Omit<T, keyof O> & { [key in keyof O]: ReturnType<O[key]> }
    >;
};

• Provide a synchronous function to coerce or transform the value(s) given on the command line for key.

  The coercion function should accept one argument, representing the parsed value from the command line, and should return a new value or throw an error. The returned value will be used as the value for key (or one of its aliases) in argv.

  If the function throws, the error will be treated as a validation failure, delegating to either a custom .fail() handler or printing the error message in the console.

  Coercion will be applied to a value after all other modifications, such as .normalize().

  Optionally .coerce() can take an object that maps several keys to their respective coercion function.

  You can also map the same function to several keys at one time. Just pass an array of keys as the first argument to .coerce().

  If you are using dot-notion or arrays, .e.g., user.email and user.password, coercion will be applied to the final object that has been parsed

method command

command: {
    <U = T>(
        command: string | readonly string[],
        description: string,
        builder?: BuilderCallback<T, U>,
        handler?: (args: ArgumentsCamelCase<U>) => void | Promise<void>,
        middlewares?: Array<MiddlewareFunction<U>>,
        deprecated?: boolean | string
    ): Argv<T>;
    <O extends { [key: string]: Options }>(
        command: string | readonly string[],
        description: string,
        builder?: O,
        handler?: (
            args: ArgumentsCamelCase<InferredOptionTypes<O>>
        ) => void | Promise<void>,
        middlewares?: MiddlewareFunction<O>[],
        deprecated?: string | boolean
    ): Argv<T>;
    <U = any>(
        command: string | readonly string[],
        description: string,
        module: CommandModule<T, U>
    ): Argv<T>;
    <U = T>(
        command: string | readonly string[],
        showInHelp: false,
        builder?: BuilderCallback<T, U>,
        handler?: (args: ArgumentsCamelCase<U>) => void | Promise<void>,
        middlewares?: MiddlewareFunction<U>[],
        deprecated?: string | boolean
    ): Argv<T>;
    <O extends { [key: string]: Options }>(
        command: string | readonly string[],
        showInHelp: false,
        builder?: O,
        handler?: (
            args: ArgumentsCamelCase<InferredOptionTypes<O>>
        ) => void | Promise<void>
    ): Argv<T>;
    <U = any>(
        command: string | readonly string[],
        showInHelp: false,
        module: CommandModule<T, U>
    ): Argv<T>;
    <U = any>(module: CommandModule<T, U>): Argv<T>;
    <U = any>(modules: CommandModule<T, U>[]): Argv<T>;
};

• Define the commands exposed by your application.

  Parameter command

  Should be a string representing the command or an array of strings representing the command and its aliases.

  Parameter description

  Use to provide a description for each command your application accepts (the values stored in argv._). Set description to false to create a hidden command. Hidden commands don't show up in the help output and aren't available for completion.

  Parameter builder

  Object to give hints about the options that your command accepts. Can also be a function. This function is executed with a yargs instance, and can be used to provide advanced command specific help.

  Note that when void is returned, the handler argv object type will not include command-specific arguments.

  Parameter handler

  Function, which will be executed with the parsed argv object.

method commandDir

commandDir: (dir: string, opts?: RequireDirectoryOptions) => Argv<T>;

• Apply command modules from a directory relative to the module calling this method.

method completion

completion: {
    (): Argv<T>;
    (cmd: string, func?: AsyncCompletionFunction): Argv<T>;
    (cmd: string, func?: SyncCompletionFunction): Argv<T>;
    (cmd: string, func?: PromiseCompletionFunction): Argv<T>;
    (cmd: string, func?: FallbackCompletionFunction): Argv<T>;
    (
        cmd: string,
        description?: string | false,
        func?: AsyncCompletionFunction
    ): Argv<T>;
    (
        cmd: string,
        description?: string | false,
        func?: SyncCompletionFunction
    ): Argv<T>;
    (
        cmd: string,
        description?: string | false,
        func?: PromiseCompletionFunction
    ): Argv<T>;
    (
        cmd: string,
        description?: string | false,
        func?: FallbackCompletionFunction
    ): Argv<T>;
};

• Enable bash/zsh-completion shortcuts for commands and options.

  If invoked without parameters, .completion() will make completion the command to output the completion script.

  Parameter cmd

  When present in argv._, will result in the .bashrc or .zshrc completion script being outputted. To enable bash/zsh completions, concat the generated script to your .bashrc or .bash_profile (or .zshrc for zsh).

  Parameter description

  Provide a description in your usage instructions for the command that generates the completion scripts.

  Parameter func

  Rather than relying on yargs' default completion functionality, which shiver me timbers is pretty awesome, you can provide your own completion method.

method config

config: {
    (): Argv<T>;
    (
        key: string | readonly string[],
        description?: string,
        parseFn?: (configPath: string) => object
    ): Argv<T>;
    (
        key: string | readonly string[],
        parseFn: (configPath: string) => object
    ): Argv<T>;
    (explicitConfigurationObject: object): Argv<T>;
};

• Tells the parser that if the option specified by key is passed in, it should be interpreted as a path to a JSON config file. The file is loaded and parsed, and its properties are set as arguments. Because the file is loaded using Node's require(), the filename MUST end in .json to be interpreted correctly.

  If invoked without parameters, .config() will make --config the option to pass the JSON config file.

  Parameter description

  Provided to customize the config (key) option in the usage string.

  Parameter explicitConfigurationObject

  An explicit configuration object

method conflicts

conflicts: {
    (key: string, value: string | readonly string[]): Argv<T>;
    (conflicts: { [key: string]: string | readonly string[] }): Argv<T>;
};

• Given the key x is set, the key y must not be set. y can either be a single string or an array of argument names that x conflicts with.

  Optionally .conflicts() can accept an object specifying multiple conflicting keys.

method count

count: {
    <K extends keyof T>(key: K | readonly K[]): Argv<
        Omit<T, K> & { [key in K]: number }
    >;
    <K extends string>(key: K | readonly K[]): Argv<T & { [key in K]: number }>;
};

• Interpret key as a boolean flag, but set its parsed value to the number of flag occurrences rather than true or false. Default value is thus 0.

method default

default: {
    <K extends keyof T, V>(key: K, value: V, description?: string): Argv<
        Omit<T, K> & { [key in K]: V }
    >;
    <K extends string, V>(key: K, value: V, description?: string): Argv<
        T & { [key in K]: V }
    >;
    <D extends { [key: string]: any }>(defaults: D, description?: string): Argv<
        Omit<T, keyof D> & D
    >;
};

• Set argv[key] to value if no option was specified in process.argv.

  Optionally .default() can take an object that maps keys to default values.

  The default value can be a function which returns a value. The name of the function will be used in the usage string.

  Optionally, description can also be provided and will take precedence over displaying the value in the usage instructions.

method demand

demand: {
    <K extends keyof T>(key: K | readonly K[], msg?: string | true): Argv<
        Defined<T, K>
    >;
    <K extends string>(key: K | readonly K[], msg?: string | true): Argv<
        T & { [key in K]: unknown }
    >;
    (key: string | readonly string[], required?: boolean): Argv<T>;
    (positionals: number, msg: string): Argv<T>;
    (positionals: number, required?: boolean): Argv<T>;
    (positionals: number, max: number, msg?: string): Argv<T>;
};

• Deprecated

  since version 6.6.0 Use '.demandCommand()' or '.demandOption()' instead

method demandCommand

demandCommand: {
    (): Argv<T>;
    (min: number, minMsg?: string): Argv<T>;
    (min: number, max?: number, minMsg?: string, maxMsg?: string): Argv<T>;
};

• Demand in context of commands. You can demand a minimum and a maximum number a user can have within your program, as well as provide corresponding error messages if either of the demands is not met.

method demandOption

demandOption: {
    <K extends keyof T>(key: K | readonly K[], msg?: string | true): Argv<
        Defined<T, K>
    >;
    <K extends string>(key: K | readonly K[], msg?: string | true): Argv<
        T & { [key in K]: unknown }
    >;
    (key: string | readonly string[], demand?: boolean): Argv<T>;
};

• Parameter key

  If is a string, show the usage information and exit if key wasn't specified in process.argv. If is an array, demand each element.

  Parameter msg

  If string is given, it will be printed when the argument is missing, instead of the standard error message.

  Parameter demand

  Controls whether the option is demanded; this is useful when using .options() to specify command line parameters.

method deprecateOption

deprecateOption: (option: string, msg?: string) => Argv<T>;

• Shows a [deprecated] notice in front of the option

method describe

describe: {
    (key: string | readonly string[], description: string): Argv<T>;
    (descriptions: { [key: string]: string }): Argv<T>;
};

• Describe a key for the generated usage information.

  Optionally .describe() can take an object that maps keys to descriptions.

method detectLocale

detectLocale: (detect: boolean) => Argv<T>;

• Should yargs attempt to detect the os' locale? Defaults to true.

method env

env: { (): Argv<T>; (prefix: string): Argv<T>; (enable: boolean): Argv<T> };

• Tell yargs to parse environment variables matching the given prefix and apply them to argv as though they were command line arguments.

  Use the "__" separator in the environment variable to indicate nested options. (e.g. prefix_nested__foo => nested.foo)

  If this method is called with no argument or with an empty string or with true, then all env vars will be applied to argv.

  Program arguments are defined in this order of precedence: 1. Command line args 2. Env vars 3. Config file/objects 4. Configured defaults

  Env var parsing is disabled by default, but you can also explicitly disable it by calling .env(false), e.g. if you need to undo previous configuration.

method epilog

epilog: (msg: string) => Argv<T>;

• A message to print at the end of the usage instructions

method epilogue

epilogue: (msg: string) => Argv<T>;

• A message to print at the end of the usage instructions

method example

example: {
    (command: string, description: string): Argv<T>;
    (command: readonly [string, string?][]): Argv<T>;
};

• Give some example invocations of your program. Inside cmd, the string $0 will get interpolated to the current script name or node command for the present script similar to how $0 works in bash or perl. Examples will be printed out as part of the help message.

method exit

exit: (code: number, err: Error) => void;

• Manually indicate that the program should exit, and provide context about why we wanted to exit. Follows the behavior set by .exitProcess().

method exitProcess

exitProcess: (enabled: boolean) => Argv<T>;

• By default, yargs exits the process when the user passes a help flag, the user uses the .version functionality, validation fails, or the command handler fails. Calling .exitProcess(false) disables this behavior, enabling further actions after yargs have been validated.

method fail

fail: (
    func: boolean | ((msg: string, err: Error, yargs: Argv<T>) => any)
) => Argv<T>;

• Method to execute when a failure occurs, rather than printing the failure message.

  Parameter func

  Is called with the failure message that would have been printed, the Error instance originally thrown and yargs state when the failure occurred.

method getCompletion

getCompletion: {
    (
        args: readonly string[],
        done: (err: Error | null, completions: readonly string[]) => void
    ): Argv<T>;
    (args: readonly string[], done?: never): Promise<readonly string[]>;
};

• Allows to programmatically get completion choices for any line.

  Parameter args

  An array of the words in the command line to complete.

  Parameter done

  The callback to be called with the resulting completions.

method getHelp

getHelp: () => Promise<string>;

• Returns a promise which resolves to a string containing the help text.

method global

global: (key: string | readonly string[]) => Argv<T>;

• Indicate that an option (or group of options) should not be reset when a command is executed

  Options default to being global.

method group

group: (key: string | readonly string[], groupName: string) => Argv<T>;

• Given a key, or an array of keys, places options under an alternative heading when displaying usage instructions

method help

help: {
    (): Argv<T>;
    (enableExplicit: boolean): Argv<T>;
    (option: string, enableExplicit: boolean): Argv<T>;
    (option: string, description?: string, enableExplicit?: boolean): Argv<T>;
};

• Configure an (e.g. --help) and implicit command that displays the usage string and exits the process. By default yargs enables help on the --help option.

  Note that any multi-char aliases (e.g. help) used for the help option will also be used for the implicit command. If there are no multi-char aliases (e.g. h), then all single-char aliases will be used for the command.

  If invoked without parameters, .help() will use --help as the option and help as the implicit command to trigger help output.

  Parameter description

  Customizes the description of the help option in the usage string.

  Parameter enableExplicit

  If false is provided, it will disable --help.

method hide

hide: (key: string) => Argv<T>;

• Hides a key from the generated usage information. Unless a --show-hidden option is also passed with --help (see showHidden()).

method implies

implies: {
    (key: string, value: string | readonly string[]): Argv<T>;
    (implies: { [key: string]: string | readonly string[] }): Argv<T>;
};

• Given the key x is set, it is required that the key y is set. y can either be the name of an argument to imply, a number indicating the position of an argument or an array of multiple implications to associate with x`.

  Optionally .implies() can accept an object specifying multiple implications.

method locale

locale: { (): string; (loc: string): Argv<T> };

• Return the locale that yargs is currently using.

  By default, yargs will auto-detect the operating system's locale so that yargs-generated help content will display in the user's language.

• Override the auto-detected locale from the user's operating system with a static locale. Note that the OS locale can be modified by setting/exporting the LC_ALL environment variable.

method middleware

middleware: (
    callbacks: MiddlewareFunction<T> | ReadonlyArray<MiddlewareFunction<T>>,
    applyBeforeValidation?: boolean
) => Argv<T>;

• Define global middleware functions to be called first, in list order, for all cli command.

  Parameter callbacks

  Can be a function or a list of functions. Each callback gets passed a reference to argv.

  Parameter applyBeforeValidation

  Set to true to apply middleware before validation. This will execute the middleware prior to validation checks, but after parsing.

method nargs

nargs: {
    (key: string, count: number): Argv<T>;
    (nargs: { [key: string]: number }): Argv<T>;
};

• The number of arguments that should be consumed after a key. This can be a useful hint to prevent parsing ambiguity.

  Optionally .nargs() can take an object of key/narg pairs.

method normalize

normalize: {
    <K extends keyof T>(key: K | readonly K[]): Argv<
        Omit<T, K> & { [key in K]: ToString<T[key]> }
    >;
    <K extends string>(key: K | readonly K[]): Argv<T & { [key in K]: string }>;
};

• The key provided represents a path and should have path.normalize() applied.

method number

number: {
    <K extends keyof T>(key: K | readonly K[]): Argv<
        Omit<T, K> & { [key in K]: ToNumber<T[key]> }
    >;
    <K extends string>(key: K | readonly K[]): Argv<T & { [key in K]: number }>;
};

• Tell the parser to always interpret key as a number.

  If key is an array, all elements will be parsed as numbers.

  If the option is given on the command line without a value, argv will be populated with undefined.

  If the value given on the command line cannot be parsed as a number, argv will be populated with NaN.

  Note that decimals, hexadecimals, and scientific notation are all accepted.

method onFinishCommand

onFinishCommand: (func: (result: any) => void) => Argv<T>;

• Method to execute when a command finishes successfully.

  Parameter func

  Is called with the successful result of the command that finished.

method option

option: {
    <K extends keyof T, O extends Options>(key: K, options: O): Argv<
        Omit<T, K> & { [key in K]: InferredOptionType<O> } & Alias<O>
    >;
    <K extends string, O extends Options>(key: K, options: O): Argv<
        T & { [key in K]: InferredOptionType<O> } & Alias<O>
    >;
    <O extends { [key: string]: Options }>(options: O): Argv<
        Omit<T, keyof O> & InferredOptionTypes<O> & Alias<O>
    >;
};

• This method can be used to make yargs aware of options that could exist. You can also pass an opt object which can hold further customization, like .alias(), .demandOption() etc. for that option.

method options

options: {
    <K extends keyof T, O extends Options>(key: K, options: O): Argv<
        Omit<T, K> & { [key in K]: InferredOptionType<O> }
    >;
    <K extends string, O extends Options>(key: K, options: O): Argv<
        T & { [key in K]: InferredOptionType<O> }
    >;
    <O extends { [key: string]: Options }>(options: O): Argv<
        Omit<T, keyof O> & InferredOptionTypes<O>
    >;
};

• This method can be used to make yargs aware of options that could exist. You can also pass an opt object which can hold further customization, like .alias(), .demandOption() etc. for that option.

method parse

parse: {
    ():
        | {
              [key in keyof Arguments<T> as
                  | key
                  | CamelCaseKey<key>]: Arguments<T>[key];
          }
        | Promise<{
              [key in keyof Arguments<T> as
                  | key
                  | CamelCaseKey<key>]: Arguments<T>[key];
          }>;
    (
        arg: string | readonly string[],
        context?: object,
        parseCallback?: ParseCallback<T>
    ):
        | {
              [key in keyof Arguments<T> as
                  | key
                  | CamelCaseKey<key>]: Arguments<T>[key];
          }
        | Promise<{
              [key in keyof Arguments<T> as
                  | key
                  | CamelCaseKey<key>]: Arguments<T>[key];
          }>;
};

• Parse args instead of process.argv. Returns the argv object. args may either be a pre-processed argv array, or a raw argument string.

  Note: Providing a callback to parse() disables the exitProcess setting until after the callback is invoked.

  Parameter context

  Provides a useful mechanism for passing state information to commands

method parseAsync

parseAsync: {
    (): Promise<{
        [key in keyof Arguments<T> as
            | key
            | CamelCaseKey<key>]: Arguments<T>[key];
    }>;
    (
        arg: string | readonly string[],
        context?: object,
        parseCallback?: ParseCallback<T>
    ): Promise<{
        [key in keyof Arguments<T> as
            | key
            | CamelCaseKey<key>]: Arguments<T>[key];
    }>;
};

method parserConfiguration

parserConfiguration: (
    configuration: Partial<ParserConfigurationOptions>
) => Argv<T>;

• Allows to configure advanced yargs features.

method parseSync

parseSync: {
    (): {
        [key in keyof Arguments<T> as
            | key
            | CamelCaseKey<key>]: Arguments<T>[key];
    };
    (
        arg: string | readonly string[],
        context?: object,
        parseCallback?: ParseCallback<T>
    ): {
        [key in keyof Arguments<T> as
            | key
            | CamelCaseKey<key>]: Arguments<T>[key];
    };
};

method pkgConf

pkgConf: (key: string | readonly string[], cwd?: string) => Argv<T>;

• Similar to config(), indicates that yargs should interpret the object from the specified key in package.json as a configuration object.

  Parameter cwd

  If provided, the package.json will be read from this location

method positional

positional: {
    <K extends keyof T, O extends PositionalOptions>(key: K, opt: O): Argv<
        Omit<T, K> & { [key in K]: InferredOptionType<O> }
    >;
    <K extends string, O extends PositionalOptions>(key: K, opt: O): Argv<
        T & { [key in K]: InferredOptionType<O> }
    >;
};

• Allows you to configure a command's positional arguments with an API similar to .option(). .positional() should be called in a command's builder function, and is not available on the top-level yargs instance. If so, it will throw an error.

method recommendCommands

recommendCommands: () => Argv<T>;

• Should yargs provide suggestions regarding similar commands if no matching command is found?

method require

require: {
    <K extends keyof T>(key: K | readonly K[], msg?: string | true): Argv<
        Defined<T, K>
    >;
    (key: string, msg: string): Argv<T>;
    (key: string, required: boolean): Argv<T>;
    (keys: readonly number[], msg: string): Argv<T>;
    (keys: readonly number[], required: boolean): Argv<T>;
    (positionals: number, required: boolean): Argv<T>;
    (positionals: number, msg: string): Argv<T>;
};

• Deprecated

  since version 6.6.0 Use '.demandCommand()' or '.demandOption()' instead

method required

required: {
    <K extends keyof T>(key: K | readonly K[], msg?: string | true): Argv<
        Defined<T, K>
    >;
    (key: string, msg: string): Argv<T>;
    (key: string, required: boolean): Argv<T>;
    (keys: readonly number[], msg: string): Argv<T>;
    (keys: readonly number[], required: boolean): Argv<T>;
    (positionals: number, required: boolean): Argv<T>;
    (positionals: number, msg: string): Argv<T>;
};

• Deprecated

  since version 6.6.0 Use '.demandCommand()' or '.demandOption()' instead

method requiresArg

requiresArg: (key: string | readonly string[]) => Argv<T>;

method scriptName

scriptName: ($0: string) => Argv<T>;

• Set the name of your script ($0). Default is the base filename executed by node (process.argv[1])

method showCompletionScript

showCompletionScript: () => Argv<T>;

• Generate a bash completion script. Users of your application can install this script in their .bashrc, and yargs will provide completion shortcuts for commands and options.

method showHelp

showHelp: {
    (consoleLevel?: string): Argv<T>;
    (printCallback: (s: string) => void): Argv<T>;
};

• Print the usage data using the console function consoleLevel for printing.

  Parameter consoleLevel

• Provide the usage data as a string.

  Parameter printCallback

  a function with a single argument.

method showHelpOnFail

showHelpOnFail: (enable: boolean, message?: string) => Argv<T>;

• By default, yargs outputs a usage string if any error is detected. Use the .showHelpOnFail() method to customize this behavior.

  Parameter enable

  If false, the usage string is not output.

  Parameter message

  Message that is output after the error message.

method showHidden

showHidden: {
    (option?: string | boolean): Argv<T>;
    (option: string, description?: string): Argv<T>;
};

• Configure the --show-hidden option that displays the hidden keys (see hide()).

  Parameter option

  If boolean, it enables/disables this option altogether. i.e. hidden keys will be permanently hidden if first argument is false. If string it changes the key name ("--show-hidden").

  Parameter description

  Changes the default description ("Show hidden options")

method showVersion

showVersion: (level?: 'error' | 'log' | ((message: string) => void)) => Argv<T>;

• Print the version data using the console function consoleLevel or the specified function.

  Parameter level

method skipValidation

skipValidation: (key: string | readonly string[]) => Argv<T>;

• Specifies either a single option key (string), or an array of options. If any of the options is present, yargs validation is skipped.

method strict

strict: { (): Argv<T>; (enabled: boolean): Argv<T> };

• Any command-line argument given that is not demanded, or does not have a corresponding description, will be reported as an error.

  Unrecognized commands will also be reported as errors.

method strictCommands

strictCommands: { (): Argv<T>; (enabled: boolean): Argv<T> };

• Similar to .strict(), except that it only applies to unrecognized commands. A user can still provide arbitrary options, but unknown positional commands will raise an error.

method strictOptions

strictOptions: { (): Argv<T>; (enabled: boolean): Argv<T> };

• Similar to .strict(), except that it only applies to unrecognized options. A user can still provide arbitrary positional options, but unknown options will raise an error.

method string

string: {
    <K extends keyof T>(key: K | readonly K[]): Argv<
        Omit<T, K> & { [key in K]: ToString<T[key]> }
    >;
    <K extends string>(key: K | readonly K[]): Argv<T & { [key in K]: string }>;
};

• Tell the parser logic not to interpret key as a number or boolean. This can be useful if you need to preserve leading zeros in an input.

  If key is an array, interpret all the elements as strings.

  .string('_') will result in non-hyphenated arguments being interpreted as strings, regardless of whether they resemble numbers.

method terminalWidth

terminalWidth: () => number;

method updateLocale

updateLocale: (obj: { [key: string]: string }) => Argv<T>;

method updateStrings

updateStrings: (obj: { [key: string]: string }) => Argv<T>;

• Override the default strings used by yargs with the key/value pairs provided in obj

  If you explicitly specify a locale(), you should do so before calling updateStrings().

method usage

usage: {
    (message: string): Argv<T>;
    <U>(
        command: string | readonly string[],
        description: string,
        builder?: (args: Argv<T>) => Argv<U>,
        handler?: (args: ArgumentsCamelCase<U>) => void | Promise<void>
    ): Argv<T>;
    <U>(
        command: string | readonly string[],
        showInHelp: boolean,
        builder?: (args: Argv<T>) => Argv<U>,
        handler?: (args: ArgumentsCamelCase<U>) => void | Promise<void>
    ): Argv<T>;
    <O extends { [key: string]: Options }>(
        command: string | readonly string[],
        description: string,
        builder?: O,
        handler?: (
            args: ArgumentsCamelCase<InferredOptionTypes<O>>
        ) => void | Promise<void>
    ): Argv<T>;
    <O extends { [key: string]: Options }>(
        command: string | readonly string[],
        showInHelp: boolean,
        builder?: O,
        handler?: (
            args: ArgumentsCamelCase<InferredOptionTypes<O>>
        ) => void | Promise<void>
    ): Argv<T>;
};