Select-Based Content / Select in Intlayer

How Select Works

In Intlayer, select-based content is achieved through the select function, which maps arbitrary string values to their corresponding content. It is the equivalent of an ICU {value, select, …} message, or of a switch statement in your application code.

Use select when the discriminant is a free-form string, a status, a plan, a platform, a role. For the other discriminants, Intlayer provides dedicated nodes:

Setting Up Select-Based Content

To set up select-based content in your Intlayer project, create a content module that includes your select definitions. Below are examples in various formats.

import { select, type Dictionary } from "intlayer";

const myPostContent = {
  key: "my_key",
  content: {
    publishStatus: select({
      draft: "This post is a draft",
      published: "This post is live",
      scheduled: "This post is scheduled",
      fallback: "Unknown status", // Optional
    }),
  },
} satisfies Dictionary;

export default myPostContent;

If no fallback is declared, the last key declared will be taken as a fallback when the provided value matches no declared case, the same contract as cond() and gender().

Type safety

The accepted argument is inferred from the declared cases:

• Without a fallback, only the declared cases are accepted, a typo is a type error.
• With a fallback, any string is accepted (the fallback covers the unmatched values) while the declared cases still autocomplete.

Why not a plain object?

It is tempting to declare a plain object and index it with the runtime value:

// ❌ Do not do this
const { publishStatus } = useIntlayer("my_key");

return <p>{publishStatus[publishType]}</p>;

The Intlayer compiler analyses your source to prune unused content and minify the remaining keys. A dynamic computed access (obj[expr]) cannot be resolved statically, so the whole branch is marked opaque: it is kept in the bundle and its keys stay un-minified.

With select(), the case resolution happens inside a function call rather than as a property access. The compiler sees a single static field access and optimises the node exactly like enu(), cond() or gender():

// ✅ Do this
const { publishStatus } = useIntlayer("my_key");

return <p>{publishStatus(publishType)}</p>;

Using Select-Based Content

import type { FC } from "react";
import { useIntlayer } from "react-intlayer";

const PostStatus: FC = () => {
  const { publishStatus } = useIntlayer("my_key");

  return (
    <div>
      <p>
        {
          /* Output: This post is a draft */
          publishStatus("draft")
        }
      </p>
      <p>
        {
          /* Output: This post is live */
          publishStatus("published")
        }
      </p>
      <p>
        {
          /* Output: Unknown status */
          publishStatus("archived")
        }
      </p>
    </div>
  );
};

export default PostStatus;

"use client";

import type { FC } from "react";
import { useIntlayer } from "next-intlayer";

const PostStatus: FC = () => {
  const { publishStatus } = useIntlayer("my_key");

  return (
    <div>
      <p>{publishStatus("draft")}</p>
      <p>{publishStatus("published")}</p>
    </div>
  );
};

export default PostStatus;

<script setup lang="ts">
import { useIntlayer } from "vue-intlayer";

const { publishStatus } = useIntlayer("my_key");
</script>

<template>
  <div>
    <p>{{ publishStatus("draft") }}</p>
    <p>{{ publishStatus("published") }}</p>
  </div>
</template>

<script lang="ts">
import { useIntlayer } from "svelte-intlayer";

const content = useIntlayer("my_key");
</script>

<div>
  <p>{$content.publishStatus("draft")}</p>
  <p>{$content.publishStatus("published")}</p>
</div>

import type { FC } from "preact";
import { useIntlayer } from "preact-intlayer";

const PostStatus: FC = () => {
  const { publishStatus } = useIntlayer("my_key");

  return (
    <div>
      <p>{publishStatus("draft")}</p>
      <p>{publishStatus("published")}</p>
    </div>
  );
};

export default PostStatus;

import type { Component } from "solid-js";
import { useIntlayer } from "solid-intlayer";

const PostStatus: Component = () => {
  const { publishStatus } = useIntlayer("my_key");

  return (
    <div>
      <p>{publishStatus("draft")}</p>
      <p>{publishStatus("published")}</p>
    </div>
  );
};

export default PostStatus;

import { Component } from "@angular/core";
import { useIntlayer } from "angular-intlayer";

@Component({
  selector: "app-post-status",
  template: `
    <div>
      <p>{{ content().publishStatus("draft") }}</p>
      <p>{{ content().publishStatus("published") }}</p>
    </div>
  `,
})
export class PostStatusComponent {
  content = useIntlayer("my_key");
}

import { installIntlayer, useIntlayer } from "vanilla-intlayer";

installIntlayer();

const content = useIntlayer("my_key").onChange((newContent) => {
  document.getElementById("status")!.textContent =
    newContent.publishStatus("draft");
});

// Initial render
document.getElementById("status")!.textContent = content.publishStatus("draft");

Combining Select with Other Nodes

Each case holds a full content node, so select composes with t(), insert(), md() and the others:

import { insert, select, t, type Dictionary } from "intlayer";

const myPostContent = {
  key: "my_key",
  content: {
    publishStatus: select({
      draft: insert(
        t({
          en: "{{name}} saved a draft",
          fr: "{{name}} a enregistré un brouillon",
        })
      ),
      published: insert(
        t({
          en: "{{name}} published the post",
          fr: "{{name}} a publié l’article",
        })
      ),
      fallback: insert(
        t({
          en: "{{name}} updated the post",
          fr: "{{name}} a mis à jour l’article",
        })
      ),
    }),
  },
} satisfies Dictionary;

export default myPostContent;

publishStatus("draft")({ name: "Alice" }); // Output: Alice saved a draft

Migrating from ICU select

Messages using the ICU select argument are imported as select nodes:

{publishType, select, draft {draft} published {published} other {Unknown}}

becomes

select({
  draft: "draft",
  published: "published",
  fallback: "Unknown",
});

The ICU other case is renamed to fallback, which is Intlayer's canonical name for a catch-all. The second argument records the ICU variable name so the message round-trips back to the exact same ICU string when exported.

An ICU select whose cases are gender values (male / female / other) is imported as a gender node instead.

Additional Resources

For more detailed information on configuration and usage, refer to the following resources:

These resources offer further insights into the setup and usage of Intlayer across various environments and frameworks.