111 lines
4.1 KiB
TypeScript
111 lines
4.1 KiB
TypeScript
/**
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* @license
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* Copyright Google LLC All Rights Reserved.
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*
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* Use of this source code is governed by an MIT-style license that can be
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* found in the LICENSE file at https://angular.io/license
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*/
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import {$localize, _global, LocalizeFn} from '../src/localize';
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export {$localize, LocalizeFn, TranslateFn} from '../src/localize';
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// Attach $localize to the global context, as a side-effect of this module.
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_global.$localize = $localize;
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// `declare global` allows us to escape the current module and place types on the global namespace
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declare global {
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/**
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* Tag a template literal string for localization.
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*
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* For example:
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*
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* ```ts
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* $localize `some string to localize`
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* ```
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*
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* **Providing meaning, description and id**
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*
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* You can optionally specify one or more of `meaning`, `description` and `id` for a localized
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* string by pre-pending it with a colon delimited block of the form:
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*
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* ```ts
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* $localize`:meaning|description@@id:source message text`;
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*
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* $localize`:meaning|:source message text`;
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* $localize`:description:source message text`;
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* $localize`:@@id:source message text`;
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* ```
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*
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* This format is the same as that used for `i18n` markers in Angular templates. See the
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* [Angular 18n guide](guide/i18n#mark-text-for-translations).
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*
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* **Naming placeholders**
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*
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* If the template literal string contains expressions, then the expressions will be automatically
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* associated with placeholder names for you.
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*
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* For example:
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*
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* ```ts
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* $localize `Hi ${name}! There are ${items.length} items.`;
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* ```
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*
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* will generate a message-source of `Hi {$PH}! There are {$PH_1} items`.
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*
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* The recommended practice is to name the placeholder associated with each expression though.
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*
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* Do this by providing the placeholder name wrapped in `:` characters directly after the
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* expression. These placeholder names are stripped out of the rendered localized string.
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*
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* For example, to name the `items.length` expression placeholder `itemCount` you write:
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*
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* ```ts
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* $localize `There are ${items.length}:itemCount: items`;
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* ```
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*
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* **Escaping colon markers**
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*
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* If you need to use a `:` character directly at the start of a tagged string that has no
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* metadata block, or directly after a substitution expression that has no name you must escape
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* the `:` by preceding it with a backslash:
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*
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* For example:
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*
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* ```ts
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* // message has a metadata block so no need to escape colon
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* $localize `:some description::this message starts with a colon (:)`;
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* // no metadata block so the colon must be escaped
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* $localize `\:this message starts with a colon (:)`;
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* ```
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*
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* ```ts
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* // named substitution so no need to escape colon
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* $localize `${label}:label:: ${}`
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* // anonymous substitution so colon must be escaped
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* $localize `${label}\: ${}`
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* ```
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*
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* **Processing localized strings:**
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*
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* There are three scenarios:
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*
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* * **compile-time inlining**: the `$localize` tag is transformed at compile time by a
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* transpiler, removing the tag and replacing the template literal string with a translated
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* literal string from a collection of translations provided to the transpilation tool.
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*
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* * **run-time evaluation**: the `$localize` tag is a run-time function that replaces and
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* reorders the parts (static strings and expressions) of the template literal string with strings
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* from a collection of translations loaded at run-time.
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*
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* * **pass-through evaluation**: the `$localize` tag is a run-time function that simply evaluates
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* the original template literal string without applying any translations to the parts. This
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* version is used during development or where there is no need to translate the localized
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* template literals.
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*
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* @param messageParts a collection of the static parts of the template string.
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* @param expressions a collection of the values of each placeholder in the template string.
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* @returns the translated string, with the `messageParts` and `expressions` interleaved together.
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*/
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const $localize: LocalizeFn;
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}
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