feat: add js/node core translation api for usage without macros

packages/babel-plugin-extract-messages/src/index.ts

@@ -132,6 +132,7 @@ function extractFromObjectExpression(
 
 export default function ({ types: t }: { types: BabelTypes }): PluginObj {
   let localTransComponentName: string
+  let localCoreI18nName: string
 
   function isTransComponent(node: Node) {
     return (
@@ -147,6 +148,11 @@ export default function ({ types: t }: { types: BabelTypes }): PluginObj {
     t.isIdentifier(node.object, { name: "i18n" }) &&
     t.isIdentifier(node.property, { name: "_" })
 
+  const isI18nTMethod = (node: Node) =>
+    t.isMemberExpression(node) &&
+    t.isIdentifier(node.object, { name: localCoreI18nName }) &&
+    t.isIdentifier(node.property, { name: "t" })
+
   function hasI18nComment(node: Node): boolean {
     return (
       node.leadingComments &&
@@ -176,6 +182,17 @@ export default function ({ types: t }: { types: BabelTypes }): PluginObj {
           // If there's no alias, consider it was imported as Trans.
           localTransComponentName = importDeclarations["Trans"] || "Trans"
         }
+
+        const coreImportDeclarations: Record<string, string> = {}
+        if (moduleName === "@lingui/core") {
+          node.specifiers.forEach((specifier) => {
+            specifier = specifier as ImportSpecifier
+            coreImportDeclarations[(specifier.imported as Identifier).name] =
+              specifier.local.name
+          })
+
+          localCoreI18nName = coreImportDeclarations["i18n"] || "i18n"
+        }
       },
 
       // Extract translation from <Trans /> component.
@@ -226,6 +243,25 @@ export default function ({ types: t }: { types: BabelTypes }): PluginObj {
 
         const firstArgument = path.node.arguments[0]
 
+        let props: Record<string, unknown> = {}
+
+        if (
+          isI18nTMethod(path.node.callee) &&
+          t.isObjectExpression(firstArgument)
+        ) {
+          props = {
+            ...extractFromObjectExpression(t, firstArgument, ctx.file.hub, [
+              "id",
+              "message",
+              "comment",
+              "context",
+            ]),
+          }
+
+          collectMessage(path, props, ctx)
+          return
+        }
+
         // support `i18n._` calls written by users in form i18n._(id, variables, descriptor)
         // without explicit annotation with comment
         // calls generated by macro has a form i18n._(/*i18n*/ {descriptor}) and
@@ -234,7 +270,7 @@ export default function ({ types: t }: { types: BabelTypes }): PluginObj {
           isI18nMethod(path.node.callee) && !firstArgument?.leadingComments
         if (!hasComment && !isNonMacroI18n) return
 
-        let props: Record<string, unknown> = {
+        props = {
           id: getTextFromExpression(
             t,
             firstArgument as Expression,
@@ -284,9 +320,7 @@ export default function ({ types: t }: { types: BabelTypes }): PluginObj {
 
       // Extract message descriptors
       ObjectExpression(path, ctx) {
-        if (!hasI18nComment(path.node)) {
-          return
-        }
+        if (!hasI18nComment(path.node)) return
 
         const props = extractFromObjectExpression(t, path.node, ctx.file.hub, [
           "id",

packages/babel-plugin-extract-messages/test/__snapshots__/index.ts.snap

@@ -9,7 +9,7 @@ exports[`@lingui/babel-plugin-extract-messages CallExpression i18n._() should ex
     message: undefined,
     origin: [
       js-call-expression.js,
-      1,
+      2,
     ],
   },
   {
@@ -19,7 +19,7 @@ exports[`@lingui/babel-plugin-extract-messages CallExpression i18n._() should ex
     message: undefined,
     origin: [
       js-call-expression.js,
-      3,
+      4,
     ],
   },
   {
@@ -29,7 +29,7 @@ exports[`@lingui/babel-plugin-extract-messages CallExpression i18n._() should ex
     message: Message with id,
     origin: [
       js-call-expression.js,
-      5,
+      6,
     ],
   },
   {
@@ -39,7 +39,7 @@ exports[`@lingui/babel-plugin-extract-messages CallExpression i18n._() should ex
     message: undefined,
     origin: [
       js-call-expression.js,
-      7,
+      8,
     ],
   },
   {
@@ -49,7 +49,22 @@ exports[`@lingui/babel-plugin-extract-messages CallExpression i18n._() should ex
     message: undefined,
     origin: [
       js-call-expression.js,
-      9,
+      10,
+    ],
+  },
+]
+`;
+
+exports[`@lingui/babel-plugin-extract-messages CallExpression i18n._() should extract messages from i18n.t aliased expression 1`] = `
+[
+  {
+    comment: Your comment,
+    context: undefined,
+    id: your.id,
+    message: Your Id Message,
+    origin: [
+      node-call-expression-aliased.js,
+      3,
     ],
   },
 ]

packages/babel-plugin-extract-messages/test/fixtures/js-call-expression.js

@@ -1,3 +1,4 @@
+
 const msg = i18n._('Message')
 
 const withDescription = i18n._('Description', {}, { comment: "description"});
@@ -8,3 +9,4 @@ const withValues = i18n._('Values {param}', { param: param });
 
 const withContext = i18n._('Some id', {},{ context: 'Context1'});
 
+const withTMessageDescriptor = i18n.t({ id: 'my.id', message: 'My Id Message', comment: 'My comment'});

packages/babel-plugin-extract-messages/test/fixtures/node-call-expression-aliased.js

@@ -0,0 +1,3 @@
+import { i18n as lingui } from '@lingui/core';
+
+const withAliasedTMessageDescriptor = lingui.t({ id: 'your.id', message: 'Your Id Message', comment: 'Your comment'});

packages/babel-plugin-extract-messages/test/index.ts

@@ -127,6 +127,13 @@ import { Trans } from "@lingui/react";
       })
     })
 
+    it("should extract messages from i18n.t aliased expression", () => {
+      expectNoConsole(() => {
+        const messages = transform("node-call-expression-aliased.js")
+        expect(messages).toMatchSnapshot()
+      })
+    })
+
     it("Should not rise warning when translation from variable", () => {
       const code = `
       i18n._(message);

packages/core/src/i18n.test.ts

@@ -286,6 +286,91 @@ describe("I18n", () => {
     })
   })
 
+  it(".t should format message from catalog", () => {
+    const messages = {
+      Hello: "Salut",
+      "My name is {name}": "Je m'appelle {name}",
+    }
+
+    const i18n = setupI18n({
+      locale: "fr",
+      messages: { fr: messages },
+    })
+
+    expect(i18n.t({ id: "Hello" })).toEqual("Salut")
+    expect(
+      i18n.t({ id: "My name is {name}", values: { name: "Fred" } })
+    ).toEqual("Je m'appelle Fred")
+
+    // missing { name }
+    expect(i18n.t({ id: "My name is {name}" })).toEqual("Je m'appelle")
+
+    // Untranslated message
+    expect(i18n.t({ id: "Missing message" })).toEqual("Missing message")
+    expect(i18n.t({ id: "Missing {name}", values: { name: "Fred" } })).toEqual(
+      "Missing Fred"
+    )
+    expect(
+      i18n.t({
+        id: "Missing with default",
+        message: "Missing {name}",
+        values: { name: "Fred" },
+      })
+    ).toEqual("Missing Fred")
+  })
+
+  it(".t allow escaping syntax characters", () => {
+    const messages = {
+      "My ''name'' is '{name}'": "Mi ''nombre'' es '{name}'",
+    }
+
+    const i18n = setupI18n({
+      locale: "es",
+      messages: { es: messages },
+    })
+
+    expect(i18n.t({ id: "My ''name'' is '{name}'" })).toEqual(
+      "Mi 'nombre' es {name}"
+    )
+  })
+
+  it(".t shouldn't compile messages in production", () => {
+    const messages = {
+      Hello: "Salut",
+      "My name is {name}": "Je m'appelle {name}",
+    }
+
+    mockEnv("production", () => {
+      const { setupI18n } = require("@lingui/core")
+      const i18n = setupI18n({
+        locale: "fr",
+        messages: { fr: messages },
+      })
+
+      expect(i18n.t({ id: "My name is {name}" }, { name: "Fred" })).toEqual(
+        "Je m'appelle {name}"
+      )
+    })
+  })
+
+  it(".t should emit missing event for missing translation", () => {
+    const i18n = setupI18n({
+      locale: "en",
+      messages: { en: { exists: "exists" } },
+    })
+
+    const handler = jest.fn()
+    i18n.on("missing", handler)
+    i18n.t({ id: "exists" })
+    expect(handler).toHaveBeenCalledTimes(0)
+    i18n.t({ id: "missing" })
+    expect(handler).toHaveBeenCalledTimes(1)
+    expect(handler).toHaveBeenCalledWith({
+      id: "missing",
+      locale: "en",
+    })
+  })
+
   describe("params.missing - handling missing translations", () => {
     it("._ should return custom string for missing translations", () => {
       const i18n = setupI18n({

packages/core/src/i18n.ts

@@ -255,6 +255,12 @@ export class I18n extends EventEmitter<Events> {
     )(values, formats)
   }
 
+  // Alternative to _. Can be used in node/js without macros
+  // uses message descriptor only
+  t(descriptor: MessageDescriptor) {
+    return this._(descriptor)
+  }
+
   date(value: string | Date, format?: Intl.DateTimeFormatOptions): string {
     return date(this._locales || this._locale, value, format)
   }

website/docs/ref/core.md

@@ -153,6 +153,28 @@ i18n._("My name is {name}", { name: "Tom" })
 i18n._("msg.id", { name: "Tom" }, { message: "My name is {name}" })
 ```
 
+### `i18n.t(messageDescriptor) (experimental)` {#i18n.t}
+
+A small wrapper on the core translation meant for NodeJS/JS usage without macros. It uses the core `_` method, but currently only accepts message descriptor. This API is prone to breaking changes.
+
+`messageDescriptor` is an object of message parameters.
+
+```ts
+import { i18n } from "@lingui/core"
+
+// Simple message
+i18n.t({ id: "Hello" })
+
+// Simple message using custom ID
+i18n.t({ id: "msg.hello", message: "Hello"})
+
+// Message with variable
+i18n.t({ id: "My name is {name}", values: { name: "Tom" } });
+
+// Message with comment, custom ID and variable
+i18n.t({ id: "msg.name", message: "My name is {name}", comment: "Message showing the passed in name", values: { name: "Tom" } });
+```
+
 ### `i18n.date(value: string | Date[, format: Intl.DateTimeFormatOptions])` {#i18n.date}
 
 > **Returns**: Formatted date string Format a date using the conventional format for the active language.