feat: support esm build

courtesy -> epoberezkin#105

build.js

@@ -5,8 +5,15 @@ var doT = require('dot');
 doT.templateSettings.strip = false;
 
 var jst = doT.compile(fs.readFileSync('./src/index.jst', 'utf8'));
-fs.writeFileSync('./index.js', jst({es6: false}));
-fs.writeFileSync('./react.js', jst({es6: false, react: true}));
-try { fs.mkdirSync('./es6'); }  catch(e) {}
-fs.writeFileSync('./es6/index.js', jst({es6: true}));
-fs.writeFileSync('./es6/react.js', jst({es6: true, react: true}));
+fs.writeFileSync('./index.js', jst({ es6: false }));
+fs.writeFileSync('./react.js', jst({ es6: false, react: true }));
+try {
+  fs.mkdirSync('./es6');
+} catch (e) {}
+fs.writeFileSync('./es6/index.js', jst({ es6: true }));
+fs.writeFileSync('./es6/react.js', jst({ es6: true, react: true }));
+try {
+  fs.mkdirSync('./esm');
+} catch (e) {}
+fs.writeFileSync('./esm/index.js', jst({ es6: true, esm: true }));
+fs.writeFileSync('./esm/react.js', jst({ es6: true, esm: true, react: true }));

package.json

@@ -3,6 +3,7 @@
   "version": "3.1.3",
   "description": "Fast deep equal",
   "main": "index.js",
+  "module": "esm/index.js",
   "scripts": {
     "eslint": "eslint *.js benchmark/*.js spec/*.js",
     "build": "node build",
@@ -55,7 +56,8 @@
     "index.d.ts",
     "react.js",
     "react.d.ts",
-    "es6/"
+    "es6/",
+    "esm/"
   ],
   "types": "index.d.ts"
 }

src/index.jst

@@ -6,7 +6,12 @@
   var envHasBigInt64Array = typeof BigInt64Array !== 'undefined';
 {{?}}
 
+{{? it.esm }}
+export default function equal(a, b) {
+{{?}}
+{{? !it.esm }}
 module.exports = function equal(a, b) {
+{{?}}
   if (a === b) return true;
 
   if (a && b && typeof a == 'object' && typeof b == 'object') {
@@ -76,4 +81,4 @@ module.exports = function equal(a, b) {
 
   // true if both NaN, false otherwise
   return a!==a && b!==b;
-};
+};