docs(core): add docs for i18n tokens (#17920)

PR Close #17920
This commit is contained in:
Olivier Combe 2017-07-04 17:07:11 +02:00 committed by Igor Minar
parent 77ef527993
commit be994496cd
4 changed files with 134 additions and 31 deletions

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@ -2,5 +2,6 @@
import { registerLocaleData } from '@angular/common';
import localeFr from '@angular/common/locales/fr';
registerLocaleData(localeFr);
// the second parameter 'fr' is optional
registerLocaleData(localeFr, 'fr');
// #enddocregion import-locale

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@ -1,7 +1,7 @@
// #docregion import-locale-extra
import { registerLocaleData } from '@angular/common';
import localeFrCa from '@angular/common/locales/fr-CA';
import localeFrCaExtra from '@angular/common/locales/extra/fr-CA';
import localeFr from '@angular/common/locales/fr';
import localeFrExtra from '@angular/common/locales/extra/fr';
registerLocaleData(localeFrCa, localeFrCaExtra);
registerLocaleData(localeFr, 'fr-FR', localeFrExtra);
// #enddocregion import-locale-extra

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@ -8,7 +8,6 @@ See the <live-example downloadOnly name="i18n">i18n Example</live-example> for a
an AOT-compiled app, translated into French.
{@a angular-i18n}
## Angular and i18n
Angular simplifies the following aspects of internationalization:
@ -62,6 +61,23 @@ For more information about Unicode locale identifiers, see the
For a complete list of locales supported by Angular, see
[the Angular repository](https://github.com/angular/angular/tree/master/packages/common/locales).
The locale identifiers used by CLDR and Angular are based on [BCP47](http://www.rfc-editor.org/rfc/bcp/bcp47.txt).
These specifications change over time; the following table maps previous identifiers to current ones at
time of writing:
| Locale name | Old locale id | New locale id |
|-------------------------------|-------------------|---------------|
| Indonesian | in | id |
| Hebrew | iw | he |
| Romanian Moldova | mo | ro-MD |
| Norwegian Bokmål | no, no-NO | nb |
| Serbian Latin | sh | sr-Latn |
| Filipino | tl | fil |
| Portuguese Brazil | pt-BR | pt |
| Chinese Simplified | zh-cn, zh-Hans-CN | zh-Hans |
| Chinese Traditional | zh-tw, zh-Hant-TW | zh-Hant |
| Chinese Traditional Hong Kong | zh-hk | zh-Hant-HK |
## i18n pipes
@ -78,6 +94,14 @@ If you want to import locale data for other languages, you can do it manually:
<code-example path="i18n/doc-files/app.locale_data.ts" region="import-locale" title="src/app/app.module.ts" linenums="false">
</code-example>
The first parameter is an object containing the locale data imported from `@angular/common/locales`.
By default, the imported locale data is registered with the locale id that is defined in the Angular
locale data itself.
If you want to register the imported locale data with another locale id, use the second parameter to
specify a custom locale id. For example, Angular's locale data defines the locale id for French as
"fr". You can use the second parameter to associate the imported French locale data with the custom
locale id "fr-FR instead of "fr".
The files in `@angular/common/locales` contain most of the locale data that you
need, but some advanced formatting options might only be available in the extra dataset that you can
import from `@angular/common/locales/extra`. An error message informs you when this is the case.
@ -118,7 +142,6 @@ in the target language.
You need to build and deploy a separate version of the app for each supported language.
{@a i18n-attribute}
### Mark text with the i18n attribute
The Angular `i18n` attribute marks translatable content. Place it on every element tag whose fixed
@ -144,7 +167,6 @@ To mark the greeting for translation, add the `i18n` attribute to the `<h1>` tag
{@a help-translator}
### Help the translator with a description and meaning
To translate a text message accurately, the translator may need additional information or context.
@ -175,7 +197,6 @@ text messages with different descriptions (not different meanings), then they ar
{@a custom-id}
### Set a custom id for persistence and maintenance
The angular i18n extractor tool generates a file with a translation unit entry for each `i18n`
@ -250,7 +271,6 @@ the same text, `Bonjour`:
{@a no-element}
### Translate text without creating an element
If there is a section of text that you would like to translate, you can wrap it in a `<span>` tag.
@ -262,7 +282,6 @@ The `<ng-container>` is transformed into an html comment:
</code-example>
{@a translate-attributes}
## Add i18n translation attributes
You also can translate attributes.
@ -286,7 +305,6 @@ You also can assign a meaning, description, and id with the `i18n-x="<meaning>|<
syntax.
{@a plural-ICU}
## Translate singular and plural
Different languages have different pluralization rules.
@ -342,7 +360,6 @@ for two, three, or any other number if the pluralization rules were different. F
</div>
{@a select-ICU}
## Select among alternative text messages
If your template needs to display different text messages depending on the value of a variable, you
@ -360,7 +377,6 @@ The message maps those values to the appropriate translations:
</code-example>
{@a nesting-ICUS}
## Nesting plural and select ICU expressions
You can also nest different ICU expressions together, as shown in this example:
@ -369,7 +385,6 @@ You can also nest different ICU expressions together, as shown in this example:
</code-example>
{@a ng-xi18n}
## Create a translation source file with _ng xi18n_
Use the `ng xi18n` command provided by the CLI to extract the text messages marked with `i18n` into
@ -394,7 +409,6 @@ package, or you can manually use the CLI Webpack plugin `ExtractI18nPlugin` from
</div>
{@a other-formats}
### Other translation formats
Angular i18n tooling supports three translation formats:
@ -422,7 +436,6 @@ The sample in this guide uses the default XLIFF 1.2 format.
</div>
{@a ng-xi18n-options}
### Other options
You can specify the output path used by the CLI to extract your translation source file with
@ -456,7 +469,6 @@ file. This information is not used by Angular, but external translation tools ma
{@a translate}
## Translate text messages
The `ng xi18n` command generates a translation source file named `messages.xlf` in the project `src`
@ -466,7 +478,6 @@ The next step is to translate this source file into the specific language
translation files. The example in this guide creates a French translation file.
{@a localization-folder}
### Create a localization folder
Most apps are translated into more than one other language. For this reason, it is standard practice
@ -500,7 +511,6 @@ For this example:
If you were translating to other languages, you would repeat these steps for each target language.
{@a translate-text-nodes}
### Translate text nodes
In a large translation project, you would send the `messages.fr.xlf` file to a French translator who
@ -544,7 +554,6 @@ This sample file is easy to translate without a special editor or knowledge of F
</div>
{@a translate-plural-select}
## Translate plural and select expressions
_Plural_ and _select_ ICU expressions are extracted separately, so they require special attention
@ -555,7 +564,6 @@ elsewhere in the source template. In this example, you know the translation unit
must be just below the translation unit for the logo.
{@a translate-plural}
### Translate _plural_
To translate a `plural`, translate its ICU format match values:
@ -567,7 +575,6 @@ You can add or remove plural cases, with each language having its own cardinalit
[CLDR plural rules](http://www.unicode.org/cldr/charts/latest/supplemental/language_plural_rules.html).)
{@a translate-select}
### Translate _select_
Below is the content of our example `select` ICU expression in the component template:
@ -598,7 +605,6 @@ Here they are together, after translation:
</code-example>
{@a translate-nested}
### Translate a nested expression
A nested expression is similar to the previous examples. As in the previous example, there are
@ -621,7 +627,6 @@ The entire template translation is complete. The next section describes how to l
into the app.
{@a app-pre-translation}
### The app and its translation file
The sample app and its translation file are now as follows:
@ -640,7 +645,6 @@ The sample app and its translation file are now as follows:
</code-tabs>
{@a merge}
## Merge the completed translation file into the app
To merge the translated text into component templates, compile the app with the completed
@ -656,12 +660,11 @@ format that Angular understands, such as `.xtb`.
How you provide this information depends upon whether you compile with
the JIT compiler or the AOT compiler.
* With [AOT](guide/i18n#aot), you pass the information as a CLI parameter.
* With [JIT](guide/i18n#jit), you provide the information at bootstrap time.
* With [AOT](guide/i18n#merge-aot), you pass the information as a CLI parameter.
* With [JIT](guide/i18n#merge-jit), you provide the information at bootstrap time.
{@a aot}
{@a merge-aot}
### Merge with the AOT compiler
The AOT (_Ahead-of-Time_) compiler is part of a build process that produces a small, fast,
@ -685,8 +688,7 @@ guide:
ng serve --aot --i18nFile=src/locale/messages.fr.xlf --i18nFormat=xlf --locale=fr
</code-example>
{@a jit}
{@a merge-jit}
### Merge with the JIT compiler
The JIT compiler compiles the app in the browser as the app loads.
@ -713,3 +715,29 @@ Then provide the `LOCALE_ID` in the main module:
<code-example path="i18n/doc-files/app.module.ts" title="src/app/app.module.ts" linenums="false">
</code-example>
{@a missing-translation}
### Report missing translations
By default, when a translation is missing, the build succeeds but generates a warning such as
`Missing translation for message "foo"`. You can configure the level of warning that is generated by
the Angular compiler:
* Error: throw an error. If you are using AOT compilation, the build will fail. If you are using JIT
compilation, the app will fail to load.
* Warning (default): show a 'Missing translation' warning in the console or shell.
* Ignore: do nothing.
If you use the AOT compiler, specify the warning level by using the CLI parameter
`--missingTranslation`. The example below shows how to set the warning level to error:
<code-example language="sh" class="code-shell">
ng serve --aot --missingTranslation=error
</code-example>
If you use the JIT compiler, specify the warning level in the compiler config at bootstrap by adding
the 'MissingTranslationStrategy' property. The example below shows how to set the warning level to
error:
<code-example path="i18n/doc-files/main.3.ts" title="src/main.ts">
</code-example>

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@ -9,21 +9,95 @@
import {InjectionToken} from '../di/injection_token';
/**
* Provide this token to set the locale of your application.
* It is used for i18n extraction, by i18n pipes (DatePipe, I18nPluralPipe, CurrencyPipe,
* DecimalPipe and PercentPipe) and by ICU expressions.
*
* See the {@linkDocs guide/i18n#setting-up-locale i18n guide} for more information.
*
* ### Example
*
* ```typescript
* import { LOCALE_ID } from '@angular/core';
* import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
* import { AppModule } from './app/app.module';
*
* platformBrowserDynamic().bootstrapModule(AppModule, {
* providers: [{provide: LOCALE_ID, useValue: 'en-US' }]
* });
* ```
*
* @experimental i18n support is experimental.
*/
export const LOCALE_ID = new InjectionToken<string>('LocaleId');
/**
* Use this token at bootstrap to provide the content of your translation file (`xtb`,
* `xlf` or `xlf2`) when you want to translate your application in another language.
*
* See the {@linkDocs guide/i18n#merge i18n guide} for more information.
*
* ### Example
*
* ```typescript
* import { TRANSLATIONS } from '@angular/core';
* import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
* import { AppModule } from './app/app.module';
*
* // content of your translation file
* const translations = '....';
*
* platformBrowserDynamic().bootstrapModule(AppModule, {
* providers: [{provide: TRANSLATIONS, useValue: translations }]
* });
* ```
*
* @experimental i18n support is experimental.
*/
export const TRANSLATIONS = new InjectionToken<string>('Translations');
/**
* Provide this token at bootstrap to set the format of your {@link TRANSLATIONS}: `xtb`,
* `xlf` or `xlf2`.
*
* See the {@linkDocs guide/i18n#merge i18n guide} for more information.
*
* ### Example
*
* ```typescript
* import { TRANSLATIONS_FORMAT } from '@angular/core';
* import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
* import { AppModule } from './app/app.module';
*
* platformBrowserDynamic().bootstrapModule(AppModule, {
* providers: [{provide: TRANSLATIONS_FORMAT, useValue: 'xlf' }]
* });
* ```
*
* @experimental i18n support is experimental.
*/
export const TRANSLATIONS_FORMAT = new InjectionToken<string>('TranslationsFormat');
/**
* Use this enum at bootstrap as an option of `bootstrapModule` to define the strategy
* that the compiler should use in case of missing translations:
* - Error: throw if you have missing translations.
* - Warning (default): show a warning in the console and/or shell.
* - Ignore: do nothing.
*
* See the {@linkDocs guide/i18n#missing-translation i18n guide} for more information.
*
* ### Example
* ```typescript
* import { MissingTranslationStrategy } from '@angular/core';
* import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
* import { AppModule } from './app/app.module';
*
* platformBrowserDynamic().bootstrapModule(AppModule, {
* missingTranslation: MissingTranslationStrategy.Error
* });
* ```
*
* @experimental i18n support is experimental.
*/
export enum MissingTranslationStrategy {