Now longer create a fake AST but let rollup handle it

src/index.js

@@ -1,7 +1,9 @@
-import { createFilter, makeLegalIdentifier } from 'rollup-pluginutils';
+import {createFilter, makeLegalIdentifier} from 'rollup-pluginutils';
 
 export default function json(options = {}) {
 	const filter = createFilter(options.include, options.exclude);
+	const indent = 'indent' in options ? options.indent : '\t';
+	const declarationType = options.preferConst ? 'const' : 'var';
 
 	return {
 		name: 'json',
@@ -11,161 +13,25 @@ export default function json(options = {}) {
 			if (!filter(id)) return null;
 
 			const data = JSON.parse(json);
-			let code = '';
-
-			const ast = {
-				type: 'Program',
-				sourceType: 'module',
-				start: 0,
-				end: null,
-				body: []
-			};
-
 			if (Object.prototype.toString.call(data) !== '[object Object]') {
-				code = `export default ${json};`;
-
-				ast.body.push({
-					type: 'ExportDefaultDeclaration',
-					start: 0,
-					end: code.length,
-					declaration: {
-						type: 'Literal',
-						start: 15,
-						end: code.length - 1,
-						value: null,
-						raw: 'null'
-					}
-				});
-			} else {
-				const indent = 'indent' in options ? options.indent : '\t';
-
-				const validKeys = [];
-				const invalidKeys = [];
-
-				Object.keys(data).forEach(key => {
-					if (key === makeLegalIdentifier(key)) {
-						validKeys.push(key);
-					} else {
-						invalidKeys.push(key);
-					}
-				});
-
-				let char = 0;
-
-				validKeys.forEach(key => {
-					const declarationType = options.preferConst ? 'const' : 'var';
-					const declaration = `export ${declarationType} ${key} = ${JSON.stringify(data[key])};`;
-
-					const start = char;
-					const end = start + declaration.length;
-
-					// generate fake AST node while we're here
-					ast.body.push({
-						type: 'ExportNamedDeclaration',
-						start: char,
-						end: char + declaration.length,
-						declaration: {
-							type: 'VariableDeclaration',
-							start: start + 7, // 'export '.length
-							end,
-							declarations: [
-								{
-									type: 'VariableDeclarator',
-									start: start + 7 + declarationType.length + 1, // `export ${declarationType} `.length
-									end: end - 1,
-									id: {
-										type: 'Identifier',
-										start: start + 7 + declarationType.length + 1, // `export ${declarationType} `.length
-										end: start + 7 + declarationType.length + 1 + key.length, // `export ${declarationType} ${key}`.length
-										name: key
-									},
-									init: {
-										type: 'Literal',
-										start: start +
-											7 +
-											declarationType.length +
-											1 +
-											key.length +
-											3, // `export ${declarationType} ${key} = `.length
-										end: end - 1,
-										value: null,
-										raw: 'null'
-									}
-								}
-							],
-							kind: declarationType
-						},
-						specifiers: [],
-						source: null
-					});
-
-					char = end + 1;
-					code += `${declaration}\n`;
-				});
-
-				const defaultExportNode = {
-					type: 'ExportDefaultDeclaration',
-					start: char,
-					end: null,
-					declaration: {
-						type: 'ObjectExpression',
-						start: char + 15,
-						end: null,
-						properties: []
-					}
-				};
-
-				char += 17 + indent.length; // 'export default {\n\t'.length'
-
-				const defaultExportRows = validKeys
-					.map(key => {
-						const row = `${key}: ${key}`;
-
-						const start = char;
-						const end = start + row.length;
-
-						defaultExportNode.declaration.properties.push({
-							type: 'Property',
-							start,
-							end,
-							method: false,
-							shorthand: false,
-							computed: false,
-							key: {
-								type: 'Identifier',
-								start,
-								end: start + key.length,
-								name: key
-							},
-							value: {
-								type: 'Identifier',
-								start: start + key.length + 2,
-								end,
-								name: key
-							},
-							kind: 'init'
-						});
-
-						char += row.length + (2 + indent.length); // ',\n\t'.length
-
-						return row;
-					})
-					.concat(
-						invalidKeys.map(key => `"${key}": ${JSON.stringify(data[key])}`)
-					);
-
-				code += `export default {\n${indent}${defaultExportRows.join(`,\n${indent}`)}\n};`;
-				ast.body.push(defaultExportNode);
-
-				const end = code.length;
-
-				defaultExportNode.declaration.end = end - 1;
-				defaultExportNode.end = end;
+				return {code: `export default ${json};\n`, map: {mappings: ''}};
 			}
 
-			ast.end = code.length;
-
-			return { ast, code, map: { mappings: '' } };
+			let namedExportCode = '';
+			const defaultExportRows = [];
+			Object.keys(data).forEach(key => {
+				if (key === makeLegalIdentifier(key)) {
+					defaultExportRows.push(`${key}: ${key}`);
+					namedExportCode += `export ${declarationType} ${key} = ${JSON.stringify(data[key])};\n`;
+				} else {
+					defaultExportRows.push(`"${key}": ${JSON.stringify(data[key])}`);
+				}
+			});
+
+			return {
+				code: namedExportCode + `export default {\n${indent}${defaultExportRows.join(`,\n${indent}`)}\n};\n`,
+				map: {mappings: ''}
+			};
 		}
 	};
 }

test/samples/array/config.json

@@ -0,0 +1,3 @@
+[
+  1, 2, 3
+]

test/samples/array/main.js

@@ -0,0 +1,3 @@
+import config from './config.json';
+
+assert.deepEqual(config, [1, 2, 3]);

test/samples/form/customIndent.js

@@ -0,0 +1,10 @@
+export var validKey = true;
+export var nested = {"subKey":"ok"};
+export var array = [1,"2"];
+export default {
+  validKey: validKey,
+  "invalid-key": 1,
+  nested: nested,
+  array: array,
+  "function": "not used"
+};

test/samples/form/default.js

@@ -0,0 +1,10 @@
+export var validKey = true;
+export var nested = {"subKey":"ok"};
+export var array = [1,"2"];
+export default {
+	validKey: validKey,
+	"invalid-key": 1,
+	nested: nested,
+	array: array,
+	"function": "not used"
+};

test/samples/form/input.json

@@ -0,0 +1,9 @@
+{
+  "validKey": true,
+  "invalid-key": 1,
+  "nested": {
+    "subKey": "ok"
+  },
+  "array": [1, "2"],
+  "function": "not used"
+}

test/samples/form/preferConst.js

@@ -0,0 +1,10 @@
+export const validKey = true;
+export const nested = {"subKey":"ok"};
+export const array = [1,"2"];
+export default {
+	validKey: validKey,
+	"invalid-key": 1,
+	nested: nested,
+	array: array,
+	"function": "not used"
+};

test/samples/literal/config.json

@@ -0,0 +1 @@
+true

test/samples/literal/main.js

@@ -0,0 +1,3 @@
+import config from './config.json';
+
+assert.equal(config, true);