TranslateCompiler API

After translations are loaded by the TranslateLoader, they are passed through the TranslateCompiler. The compiler prepares each message for faster lookup at translate time. For example, ngx-translate-messageformat-compiler uses this API to compile ICU MessageFormat strings into interpolation functions.

The matching provider helper is provideTranslateCompiler(). See Configuration → Provider helpers.

API

export abstract class TranslateCompiler {
  abstract compile(value: string, lang: string): InterpolatableTranslation;
  abstract compileTranslations(
    translations: TranslationObject,
    lang: string,
  ): InterpolatableTranslationObject;
}

API Description

• compile() compiles a single translation value.
• compileTranslations() iterates over a full translation object, calling compile() on each value.

When a single message is requested, the TranslateParser consumes the compiler’s result. The default parser behaves differently depending on the result type:

• string → standard {{placeholder}} substitution.
• InterpolateFunction → called with the interpolation parameters; expected to return a string:

const compiledTranslations = {
  hello: (params: any) => `Hello ${params.name}!`,
};

If you ship translations that are already in their final interpolator-ready form (e.g. emitted by a build step), store them with setCompiledTranslation() to bypass the compiler.

Registering a Custom Compiler

app.config.ts

import { provideTranslateService, provideTranslateCompiler } from '@ngx-translate/core';

export const appConfig: ApplicationConfig = {
  providers: [
    provideTranslateService({
      compiler: provideTranslateCompiler(MyCompiler),
    }),
  ],
};

The factory form is also supported:

provideTranslateService({
  compiler: provideTranslateCompiler(() => new MyCompiler({ icu: true })),
})

How to Build a Custom Compiler

For a step-by-step guide see Custom Translation Compilers.