fix: target ES6 for ESM bundles, fixes #526

.eslintrc.json

@@ -32,7 +32,7 @@
     "@typescript-eslint/no-unused-vars": ["error", { "vars": "all", "args": "none", "ignoreRestSiblings": false }]
   },
   "overrides": [{
-    "files": ["**/*.js", "*.js"],
+    "files": ["**/*.js", "**/*.mjs"],
     "rules": {
       "@typescript-eslint/no-var-requires": "off"
     }

package.json

@@ -11,7 +11,7 @@
   },
   "types": "dist/liquid.d.ts",
   "scripts": {
-    "lint": "eslint \"**/*.ts\" .",
+    "lint": "eslint \"**/*.mjs\" \"**/*.ts\" .",
     "check": "npm run build && npm test && npm run lint && npm run perf:diff",
     "test": "nyc mocha \"test/**/*.ts\"",
     "test:e2e": "mocha \"test/e2e/**/*.ts\"",
@@ -20,7 +20,7 @@
     "perf:engines": "cd benchmark && npm run engines",
     "postversion": "npm run build:dist",
     "build": "npm run build:dist && npm run build:docs",
-    "build:dist": "rollup -c rollup.config.ts",
+    "build:dist": "rollup -c rollup.config.mjs",
     "build:docs": "bin/build-docs.sh"
   },
   "bin": {

rollup.config.mjs

@@ -1,9 +1,10 @@
 import { uglify } from 'rollup-plugin-uglify'
-import pkg from './package.json'
 import typescript from 'rollup-plugin-typescript2'
 import replace from 'rollup-plugin-replace'
 import versionInjector from 'rollup-plugin-version-injector'
+import { createRequire } from 'module'
 
+const pkg = createRequire(import.meta.url)('./package.json')
 const version = process.env.VERSION || pkg.version
 const sourcemap = true
 const banner = `/*
@@ -14,16 +15,16 @@ const banner = `/*
 const treeshake = {
   propertyReadSideEffects: false
 }
-const tsconfig = {
+const tsconfig = (target) => ({
   tsconfigOverride: {
     include: [ 'src' ],
     exclude: [ 'test', 'benchmark' ],
     compilerOptions: {
-      target: 'es5',
+      target,
       module: 'ES2015'
     }
   }
-}
+})
 const versionInjection = versionInjector({
   injectInComments: false,
   injectInTags: {
@@ -60,7 +61,7 @@ const nodeCjs = {
     banner
   }],
   external: ['path', 'fs'],
-  plugins: [versionInjection, typescript(tsconfig)],
+  plugins: [versionInjection, typescript(tsconfig('es5'))],
   treeshake,
   input
 }
@@ -75,7 +76,7 @@ const nodeEsm = {
   plugins: [
     versionInjection,
     replace(esmRequire),
-    typescript(tsconfig)
+    typescript(tsconfig('es6'))
   ],
   treeshake,
   input
@@ -92,7 +93,7 @@ const browserEsm = {
     versionInjection,
     replace(browserFS),
     replace(browserStream),
-    typescript(tsconfig)
+    typescript(tsconfig('es6'))
   ],
   treeshake,
   input
@@ -110,7 +111,7 @@ const browserUmd = {
     versionInjection,
     replace(browserFS),
     replace(browserStream),
-    typescript(tsconfig)
+    typescript(tsconfig('es5'))
   ],
   treeshake,
   input
@@ -128,7 +129,7 @@ const browserMin = {
     versionInjection,
     replace(browserFS),
     replace(browserStream),
-    typescript(tsconfig),
+    typescript(tsconfig('es5')),
     uglify()
   ],
   treeshake,