• Version 13.3.8
  • Published
  • 558 kB
  • 3 dependencies
  • MIT license


npm i @angular/localize
yarn add @angular/localize
pnpm add @angular/localize


Angular - library for localizing messages



function clearTranslations

clearTranslations: () => void;
  • Remove all translations for $localize, if doing runtime translation.

    All translations that had been loading into memory using loadTranslations() will be removed.

    See Also

    • loadTranslations() for loading translations at runtime.

    • $localize for tagging messages as needing to be translated.

function loadTranslations

loadTranslations: (translations: Record<MessageId, TargetMessage>) => void;
  • Load translations for use by $localize, if doing runtime translation.

    If the $localize tagged strings are not going to be replaced at compiled time, it is possible to load a set of translations that will be applied to the $localize tagged strings at runtime, in the browser.

    Loading a new translation will overwrite a previous translation if it has the same MessageId.

    Note that $localize messages are only processed once, when the tagged string is first encountered, and does not provide dynamic language changing without refreshing the browser. Loading new translations later in the application life-cycle will not change the translated text of messages that have already been translated.

    The message IDs and translations are in the same format as that rendered to "simple JSON" translation files when extracting messages. In particular, placeholders in messages are rendered using the {$PLACEHOLDER_NAME} syntax. For example the message from the following template:

    <div i18n>pre<span>inner-pre<b>bold</b>inner-post</span>post</div>

    would have the following form in the translations map:


    Parameter translations

    A map from message ID to translated message.

    These messages are processed and added to a lookup based on their MessageId.

    See Also

    • clearTranslations() for removing translations loaded using this function.

    • $localize for tagging messages as needing to be translated.

function ɵfindEndOfBlock

ɵfindEndOfBlock: (cooked: string, raw: string) => number;
  • Find the end of a "marked block" indicated by the first non-escaped colon.

    Parameter cooked

    The cooked string (where escaped chars have been processed)

    Parameter raw

    The raw string (where escape sequences are still in place)


    the index of the end of block marker


    an error if the block is unterminated

function ɵisMissingTranslationError

ɵisMissingTranslationError: (e: any) => e is MissingTranslationError;

    function ɵmakeParsedTranslation

    ɵmakeParsedTranslation: (
    messageParts: string[],
    placeholderNames?: string[]
    ) => ParsedTranslation;
    • Create a ParsedTranslation from a set of messageParts and placeholderNames.

      Parameter messageParts

      The message parts to appear in the ParsedTranslation.

      Parameter placeholderNames

      The names of the placeholders to intersperse between the messageParts.

    function ɵmakeTemplateObject

    ɵmakeTemplateObject: (cooked: string[], raw: string[]) => TemplateStringsArray;
    • Create the specialized array that is passed to tagged-string tag functions.

      Parameter cooked

      The message parts with their escape codes processed.

      Parameter raw

      The message parts with their escaped codes as-is.

    function ɵparseMessage

    ɵparseMessage: (
    messageParts: TemplateStringsArray,
    expressions?: readonly any[],
    location?: SourceLocation,
    messagePartLocations?: (SourceLocation | undefined)[],
    expressionLocations?: (SourceLocation | undefined)[]
    ) => ParsedMessage;
    • Parse a $localize tagged string into a structure that can be used for translation or extraction.

      See ParsedMessage for an example.

    function ɵparseMetadata

    ɵparseMetadata: (cooked: string, raw: string) => MessageMetadata;
    • Parse the given message part (cooked + raw) to extract the message metadata from the text.

      If the message part has a metadata block this function will extract the meaning, description, customId and legacyId (if provided) from the block. These metadata properties are serialized in the string delimited by |, @@ and respectively.

      (Note that is the LEGACY_ID_INDICATOR - see constants.ts.)

      For example:


      Parameter cooked

      The cooked version of the message part to parse.

      Parameter raw

      The raw version of the message part to parse.


      A object containing any metadata that was parsed from the message part.

    function ɵparseTranslation

    ɵparseTranslation: (messageString: TargetMessage) => ParsedTranslation;
    • Parse the messageParts and placeholderNames out of a target message.

      Used by loadTranslations() to convert target message strings into a structure that is more appropriate for doing translation.

      Parameter message

      the message to be parsed.

    function ɵsplitBlock

    ɵsplitBlock: (cooked: string, raw: string) => { text: string; block?: string };
    • Split a message part (cooked + raw) into an optional delimited "block" off the front and the rest of the text of the message part.

      Blocks appear at the start of message parts. They are delimited by a colon : character at the start and end of the block.

      If the block is in the first message part then it will be metadata about the whole message: meaning, description, id. Otherwise it will be metadata about the immediately preceding substitution: placeholder name.

      Since blocks are optional, it is possible that the content of a message block actually starts with a block marker. In this case the marker must be escaped \:.

      Parameter cooked

      The cooked version of the message part to parse.

      Parameter raw

      The raw version of the message part to parse.


      An object containing the text of the message part and the text of the block, if it exists.


      an error if the block is unterminated

    function ɵtranslate

    ɵtranslate: (
    translations: Record<string, ParsedTranslation>,
    messageParts: TemplateStringsArray,
    substitutions: readonly any[]
    ) => [TemplateStringsArray, readonly any[]];
    • Translate the text of the $localize tagged-string (i.e. messageParts and substitutions) using the given translations.

      The tagged-string is parsed to extract its messageId which is used to find an appropriate ParsedTranslation. If this doesn't match and there are legacy ids then try matching a translation using those.

      If one is found then it is used to translate the message into a new set of messageParts and substitutions. The translation may reorder (or remove) substitutions as appropriate.

      If there is no translation with a matching message id then an error is thrown. If a translation contains a placeholder that is not found in the message being translated then an error is thrown.


    class ɵMissingTranslationError

    class MissingTranslationError extends Error {}


      constructor(parsedMessage: ParsedMessage);

        property parsedMessage

        readonly parsedMessage: ParsedMessage;


          interface ɵParsedMessage

          interface ParsedMessage extends MessageMetadata {}
          • Information parsed from a $localize tagged string that is used to translate it.

            For example:

            const name = 'Jo Bloggs';
            $localize`Hello ${name}:title@@ID:!`;

            May be parsed into:

            id: '6998194507597730591',
            substitutions: { title: 'Jo Bloggs' },
            messageString: 'Hello {$title}!',
            placeholderNames: ['title'],
            associatedMessageIds: { title: 'ID' },

          property associatedMessageIds

          associatedMessageIds?: Record<string, MessageId>;
          • An optional mapping of placeholder names to associated MessageIds. This can be used to match ICU placeholders to the message that contains the ICU.

          property id

          id: MessageId;
          • The key used to look up the appropriate translation target.

          property messagePartLocations

          messagePartLocations?: (SourceLocation | undefined)[];
          • An optional mapping of message parts to source locations

          property messageParts

          messageParts: string[];
          • The static parts of the message.

          property placeholderNames

          placeholderNames: string[];
          • The names of the placeholders that will be replaced with substitutions.

          property substitutionLocations

          substitutionLocations?: Record<string, SourceLocation | undefined>;
          • An optional mapping of placeholder names to source locations

          property substitutions

          substitutions: Record<string, any>;
          • A mapping of placeholder names to substitution values.

          interface ɵParsedTranslation

          interface ParsedTranslation extends MessageMetadata {}
          • A translation message that has been processed to extract the message parts and placeholders.

          property messageParts

          messageParts: TemplateStringsArray;

            property placeholderNames

            placeholderNames: string[];

              interface ɵSourceLocation

              interface SourceLocation {}
              • The location of the message in the source file.

                The line and column values for the start and end properties are zero-based.

              property end

              end: {
              line: number;
              column: number;

                property file

                file: AbsoluteFsPathLocalizeCopy;

                  property start

                  start: {
                  line: number;
                  column: number;

                    property text

                    text?: string;

                      Type Aliases

                      type ɵMessageId

                      type MessageId = string;
                      • A string that uniquely identifies a message, to be used for matching translations.

                      type ɵParsedTranslations

                      type ParsedTranslations = Record<MessageId, ParsedTranslation>;
                      • The internal structure used by the runtime localization to translate messages.

                      type ɵSourceMessage

                      type SourceMessage = string;
                      • A string containing a translation source message.

                        I.E. the message that indicates what will be translated from.

                        Uses {$placeholder-name} to indicate a placeholder.

                      type ɵTargetMessage

                      type TargetMessage = string;
                      • A string containing a translation target message.

                        I.E. the message that indicates what will be translated to.

                        Uses {$placeholder-name} to indicate a placeholder.

                      Package Files (4)

                      Dependencies (3)

                      Dev Dependencies (0)

                      No dev dependencies.

                      Peer Dependencies (2)


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