fix: explicitly fullfill json module to avoid json module dep issue in npm package

Author: 3cp

src/trace.js

@@ -3,6 +3,7 @@ import hackMoment from './transformers/hack-moment';
 import alias from './transformers/alias';
 import conventionalAlias from './transformers/conventional-alias';
 import text from './transformers/text';
+import json from './transformers/json';
 import wasm from './transformers/wasm';
 import esmToCjs from './transformers/esm-to-cjs';
 import replace from './transformers/replace';
@@ -56,6 +57,8 @@ export default function(unit, opts = {}) {
     );
   } else if (extname === '.wasm') {
     transformers.push(wasm);
+  } else if (extname === '.json') {
+    transformers.push(json);
   } else {
     // use text! for everything else including unknown extname
     transformers.push(text);

src/transformers/json.js

@@ -0,0 +1,26 @@
+// wrap html/svg/css into amd
+export default function (unit) {
+  const {moduleId, contents, sourceMap, path} = unit;
+
+  const newUnit = {
+    defined: [moduleId, 'text!' + moduleId],
+    contents: `define('text!${moduleId}',function(){return ${JSON.stringify(contents)};});define('${moduleId}',['text!${moduleId}'],function(m){return JSON.parse(m);});`,
+    deps: []
+  };
+
+  if (!sourceMap) {
+    const filename = path.replace(/\\/g, '/');
+    // an identity source map to just showing the original file in browser dev console.
+    // there would not be any runtime error leading to this mapping.
+    newUnit.sourceMap = {
+      version: 3,
+      file: filename,
+      sources: [filename],
+      mappings: 'AAAA',
+      names: [],
+      sourcesContent: [contents]
+    };
+  }
+
+  return newUnit;
+}

test/trace.spec.js

@@ -214,7 +214,7 @@ test('trace transforms json', t => {
   trace(unit).then(traced => {
     t.deepEqual(traced, {
       path: 'src/foo/bar.json',
-      contents: "define('text!foo/bar.json',function(){return \"{\\\"a\\\":1}\";});",
+      contents: "define('text!foo/bar.json',function(){return \"{\\\"a\\\":1}\";});define('foo/bar.json',['text!foo/bar.json'],function(m){return JSON.parse(m);});",
       sourceMap: {
         version: 3,
         file: 'src/foo/bar.json',
@@ -224,7 +224,7 @@ test('trace transforms json', t => {
         sourcesContent: [ '{"a":1}' ]
       },
       moduleId: 'foo/bar.json',
-      defined: ['text!foo/bar.json'],
+      defined: ['foo/bar.json', 'text!foo/bar.json'],
       deps: []
     })
     t.end();

test/transformers/json.spec.js

@@ -0,0 +1,50 @@
+import test from 'tape';
+import json from '../../src/transformers/json';
+
+test('json wraps json into amd module', t => {
+  const source = '{"a":1}';
+  const target = "define('text!a.json',function(){return \"{\\\"a\\\":1}\";});define('a.json',['text!a.json'],function(m){return JSON.parse(m);});";
+
+  t.deepEqual(json({
+    moduleId: 'a.json',
+    contents: source,
+    path: 'src/a.json'
+  }), {
+    defined: ['a.json', 'text!a.json'],
+    deps: [],
+    contents: target,
+    sourceMap: {
+      version: 3,
+      file: 'src/a.json',
+      sources: ['src/a.json'],
+      mappings: 'AAAA',
+      names: [],
+      sourcesContent: [source]
+    }
+  });
+  t.end();
+});
+
+test('json skips identity source map when there is existing map', t => {
+  const source = '{"a":1}';
+  const target = "define('text!a.json',function(){return \"{\\\"a\\\":1}\";});define('a.json',['text!a.json'],function(m){return JSON.parse(m);});";
+
+  t.deepEqual(json({
+    moduleId: 'a.json',
+    contents: source,
+    path: 'src/a.json',
+    sourceMap: {
+      version: 3,
+      file: 'src/a.json',
+      sources: ['src/a.json'],
+      mappings: '',
+      names: [],
+      sourcesContent: [source]
+    }
+  }), {
+    defined: ['a.json', 'text!a.json'],
+    deps: [],
+    contents: target
+  });
+  t.end();
+});