Expose FluentSerializer.serializeExpression

fluent-syntax/src/serializer.js

@@ -18,6 +18,10 @@ export default class FluentSerializer {
   }
 
   serialize(resource) {
+    if (resource.type !== 'Resource') {
+      throw new Error(`Unknown resource type: ${resource.type}`);
+    }
+
     const parts = [];
 
     if (resource.comment) {
@@ -66,6 +70,10 @@ export default class FluentSerializer {
         throw new Error(`Unknown entry type: ${entry.type}`);
     }
   }
+
+  serializeExpression(expr) {
+    return serializeExpression(expr);
+  }
 }
 
 
@@ -176,7 +184,13 @@ function serializePlaceable(placeable) {
     case 'Placeable':
       return `{${serializePlaceable(expr)}}`;
     case 'SelectExpression':
-      return `{${serializeSelectExpression(expr)}}`;
+      // Special-case select expression to control the whitespace around the
+      // opening and the closing brace.
+      return expr.expression
+        // A select expression with a selector.
+        ? `{ ${serializeSelectExpression(expr)}}`
+        // A variant list without a selector.
+        : `{${serializeSelectExpression(expr)}}`;
     default:
       return `{ ${serializeExpression(expr)} }`;
   }
@@ -199,6 +213,8 @@ function serializeExpression(expr) {
       return serializeVariantExpression(expr);
     case 'CallExpression':
       return serializeCallExpression(expr);
+    case 'SelectExpression':
+      return serializeSelectExpression(expr);
     default:
       throw new Error(`Unknown expression type: ${expr.type}`);
   }
@@ -229,7 +245,7 @@ function serializeSelectExpression(expr) {
   const parts = [];
 
   if (expr.expression) {
-    const selector = ` ${serializeExpression(expr.expression)} ->`;
+    const selector = `${serializeExpression(expr.expression)} ->`;
     parts.push(selector);
   }
 

fluent-syntax/test/serializer_test.js

@@ -1,17 +1,36 @@
 import assert from 'assert';
 import { ftl } from './util';
 
-import { parse, serialize } from '../src';
+import { FluentParser, FluentSerializer } from '../src';
 
 
-function pretty(text) {
-  const res = parse(text);
-  return serialize(res, {
-    withJunk: false
+suite('Serialize resource', function() {
+  let pretty;
+
+  setup(function() {
+    const parser = new FluentParser();
+    const serializer = new FluentSerializer({
+      withJunk: false
+    });
+
+    pretty = function pretty(text) {
+      const res = parser.parse(text);
+      return serializer.serialize(res);
+    }
+  });
+
+  test('invalid resource', function() {
+    const serializer = new FluentSerializer();
+    assert.throws(
+      () => serializer.serialize(null),
+      /Cannot read property 'type'/
+    );
+    assert.throws(
+      () => serializer.serialize({}),
+      /Unknown resource type/
+    );
   });
-}
 
-suite('Serializer', function() {
   test('simple message', function() {
     const input = ftl`
       foo = Foo
@@ -400,3 +419,90 @@ suite('Serializer', function() {
     assert.equal(pretty(input), input);
   });
 });
+
+suite('Serialize expression', function() {
+  let pretty;
+
+  setup(function() {
+    const parser = new FluentParser();
+    const serializer = new FluentSerializer({
+      withJunk: false
+    });
+
+    pretty = function pretty(text) {
+      const {value: {elements: [placeable]}} = parser.parseEntry(text);
+      return serializer.serializeExpression(placeable.expression);
+    }
+  });
+
+  test('invalid expression', function() {
+    const serializer = new FluentSerializer();
+    assert.throws(
+      () => serializer.serializeExpression(null),
+      /Cannot read property 'type'/
+    );
+    assert.throws(
+      () => serializer.serializeExpression({}),
+      /Unknown expression type/
+    );
+  });
+
+  test('string expression', function() {
+    const input = ftl`
+      foo = { "str" }
+    `;
+    assert.equal(pretty(input), '"str"');
+  });
+
+  test('number expression', function() {
+    const input = ftl`
+      foo = { 3 }
+    `;
+    assert.equal(pretty(input), '3');
+  });
+
+  test('message reference', function() {
+    const input = ftl`
+      foo = { msg }
+    `;
+    assert.equal(pretty(input), 'msg');
+  });
+
+  test('external argument', function() {
+    const input = ftl`
+      foo = { $ext }
+    `;
+    assert.equal(pretty(input), '$ext');
+  });
+
+  test('attribute expression', function() {
+    const input = ftl`
+      foo = { msg.attr }
+    `;
+    assert.equal(pretty(input), 'msg.attr');
+  });
+
+  test('variant expression', function() {
+    const input = ftl`
+      foo = { -msg[variant] }
+    `;
+    assert.equal(pretty(input), '-msg[variant]');
+  });
+
+  test('call expression', function() {
+    const input = ftl`
+      foo = { BUILTIN(3.14, kwarg: "value") }
+    `;
+    assert.equal(pretty(input), 'BUILTIN(3.14, kwarg: "value")');
+  });
+
+  test('select expression', function() {
+    const input = ftl`
+      foo =
+          { $num ->
+              *[one] One
+          }
+    `;
+    assert.equal(pretty(input), '$num ->\n   *[one] One\n');
+  });
+});