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\n\t\n\t\t\r\n\r\n\r\n\r\n\r\n\n\t
\n A lightweight blazing-fast internationalization (i18n) library for your next web-based project\n Go here to see a demo https://appnest-demo.firebaseapp.com/lit-translate.\n
\n\n![](\"https://raw.githubusercontent.com/andreasbm/lit-translate/master/example.gif\")
\n\n\r\n[](#table-of-contents)\r\n\r\n## ➤ Table of Contents\n\n* [➤ Installation](#-installation)\r\n* [➤ 1. Define the translations](#-1-define-the-translations)\r\n* [➤ 2. Register the translate config](#-2-register-the-translate-config)\r\n* [➤ 3. Set the language](#-3-set-the-language)\r\n* [➤ 4. Get the translations](#-4-get-the-translations)\r\n* [➤ 5. Interpolate values](#-5-interpolate-values)\r\n* [➤ 6. Use the `translate` directive with `lit-html`](#-6-use-the-translate-directive-with-lit-html)\r\n* [➤ Customize! (advanced)](#-customize-advanced)\r\n* [➤ Wait for strings to be loaded before displaying the component](#-wait-for-strings-to-be-loaded-before-displaying-the-component)\r\n* [➤ License](#-license)\n\n\r\n[](#installation)\r\n\r\n## ➤ Installation\n\n```javascript\nnpm i @appnest/lit-translate\n```\n\r\n[](#1-define-the-translations)\r\n\r\n## ➤ 1. Define the translations\n\nTo take advantage of the translation features you need to be able to provide your translations as a JSON structure. You are able to configure how these strings are loaded, but to make things simple we encourage you to maintain your translations in `.json` files - one for each language you support.\n\n```json\n// en.json\n{\n \"header\": {\n \"title\": \"Hello\",\n \"subtitle\": \"World\"\n },\n \"cta\": {\n \"awesome\": \"things are awesome!\",\n \"cats\": \"Cats\"\n }\n}\n```\n\n\r\n[](#2-register-the-translate-config)\r\n\r\n## ➤ 2. Register the translate config\n\nUse the `registerTranslateConfig` function to register a loader that loads and parses the translations based on a language identifier. In the example below, a loader is registered which loads a `.json` file with translations for a given language.\n\n```typescript\nimport { registerTranslateConfig } from \"@appnest/lit-translate\";\n\nregisterTranslateConfig({\n loader: lang => fetch(`/assets/i18n/${lang}.json`).then(res => res.json())\n});\n```\n\n\r\n[](#3-set-the-language)\r\n\r\n## ➤ 3. Set the language\n\nInvoke the `use` function to set a language. This function will use the registered loader from step 1 to load the strings for the language and dispatch a global `langChanged` event.\n\n```typescript\nimport { use } from \"@appnest/lit-translate\";\n\nuse(\"en\");\n```\n\n\r\n[](#4-get-the-translations)\r\n\r\n## ➤ 4. Get the translations\n\nTo get a translation use the `get` function. Give this function a string of keys (using the dot notation) that points to the desired translation in the JSON structure. The example below is based on the translations defined in `step 1`.\n\n```typescript\nimport { get } from \"@appnest/lit-translate\";\n\nget(\"header.title\"); // \"Hello\"\nget(\"header.subtitle\"); // \"World\"\n```\n\n\r\n[](#5-interpolate-values)\r\n\r\n## ➤ 5. Interpolate values\n\nWhen using the `get` function it is possible to interpolate values (eg. replace the placeholders with content). As default, you can simply use the `key` syntax in your translations and provide an object with values replacing those defined in the translations when using the `get` function. The example below is based on the strings defined in `step 1`.\n\n```typescript\nimport { get } from \"@appnest/lit-translate\";\n\nget(\"cta.awesome\", { things: get(\"cta.cats\") }); // Cats are awesome!\n```\n\n\n\r\n[](#6-use-the-translate-directive-with-lit-html)\r\n\r\n## ➤ 6. Use the `translate` directive with `lit-html`\n\nIf you are using `lit-html` you might want to use the `translate` directive. This directive makes sure to automatically update all of the translated parts when the `use` function is called and the global `langChanged` event is dispatched. Note that values have to be returned from callbacks to refresh the translated values.\n\n```typescript\nimport { translate } from \"@appnest/lit-translate\";\n\nclass MyComponent extends LitElement {\n render () {\n html`\n ${translate(\"header.subtitle\")}
\n ${translate(\"cta.awesome\", { things: () => get(\"cta.cats\") })}\n `;\n }\n}\n```\n\n\r\n[](#customize-advanced)\r\n\r\n## ➤ Customize! (advanced)\n\nIf you want you can customize just about anything by overwriting the configuration hooks. Below is an example on what you might want to customize.\n\n```typescript\nimport { registerTranslateConfig, extract, LanguageIdentifier, Values, Key, ITranslateConfig, ValuesCallback, Translations } from \"@appnest/lit-translate\";\n\nregisterTranslateConfig({\n\n // Loads the language from the correct path\n loader: (lang: LanguageIdentifier) => fetch(`/assets/i18n/${lang}.json`).then(res => res.json()),\n\n // Interpolate the values using a [[key]] syntax.\n interpolate: (text: string, values: Values | ValuesCallback) => {\n for (const [key, value] of Object.entries(extract(values))) {\n text = text.replace(new RegExp(`\\[\\[${key}\\]\\]`), String(extract(value)));\n }\n\n return text;\n },\n\n // Returns a string for a given key\n lookup: (key: Key, config: ITranslateConfig) => {\n\n // Split the key in parts (example: hello.world)\n const parts = key.split(\".\");\n\n // Find the string by traversing through the strings matching the chain of keys\n let string: Strings | string | undefined = config.strings;\n\n // Do not continue if the string is not defined or if we have traversed all of the key parts\n while (string != null && parts.length > 0) {\n string = (string as Strings)[parts.shift()!];\n }\n\n // Make sure the string is in fact a string!\n return string != null ? string.toString() : null;\n },\n\n // Formats empty placeholders (eg. !da.headline.title!)\n empty: (key: Key, config: ITranslateConfig) => `!${config.lang}.${key}!`\n});\n```\n\n\r\n[](#wait-for-strings-to-be-loaded-before-displaying-the-component)\r\n\r\n## ➤ Wait for strings to be loaded before displaying the component\n\nSometimes you want to avoid the empty placeholders being shown initially before any of the translation strings has been loaded. To avoid this issue you might want to defer the first update of the component. Here's an example of what you could do if using `lit-element`.\n\n```typescript\nimport { use, translate } from \"@appnest/lit-translate\";\nimport { LitElement, customElement } from \"lit-element\";\n\n@customElement(\"my-root-component\")\nexport class MyRootComponent extends LitElement {\n\n // Defer the first update of the component until the strings has been loaded to avoid empty strings being shown\n private hasLoadedStrings = false;\n protected shouldUpdate (changedProperties: PropertyValues) {\n return this.hasLoadedStrings && super.shouldUpdate(changedProperties);\n }\n\n // Load the initial language and mark that the strings has been loaded.\n async connectedCallback () {\n await use(\"en\");\n this.hasLoadedStrings = true;\n super.connectedCallback();\n }\n\n protected render (): TemplateResult {\n return html`\n${translate(\"title\")}
\n `;\n }\n}\n```\n\n\n\r\n[](#license)\r\n\r\n## ➤ License\n\t\nLicensed under [MIT](https://opensource.org/licenses/MIT).","readmeFilename":"README.md"}