SyntaxError: In strict mode code, functions can only be declared at top level or immediately within another function.

[whtsky]

Encountered an error while minifying vendor.87087612.chunk.js:
SyntaxError: In strict mode code, functions can only be declared at top level or immediately within another function.
  44936 | 
  44937 | if (__DEV__) {
> 44938 |   function printWarning(format, args) {
        |  ^
  44939 |     var len = arguments.length;
  44940 |     args = new Array(len > 2 ? len - 2 : 0);
  44941 |     for (var key = 2; key < len; key++) {

[TrySound]

@whtsky Show your webpack config

[whtsky]

https://github.com/whtsky/antd-build-error/blob/master/webpack.config.js

[TrySound]

@whtsky Do you get this with default uglify?

[whtsky]

webpack 4 ships with uglify-es(which is out of maintaince) but we want to use uglify-js so I didn't try actually. But I assume using webpack 3 + uglifyjs would error too.

[TrySound]

@whtsky Well, if you don't have any problems with uglify-es just keep using webpack default. They will swap to terser (uglify-es fork) soon. Unsupported package won't introduce any breaking changes.

[TrySound]

By the way webpack4 in production mode works as expected.

[whtsky]

if you don't have any problems with uglify-es

uglify-es can't handle inline function correctly: mishoo/UglifyJS#2842.
I know they will swap to terser soon, but since our web app are targeting IE 10, we can make sure we don't ship ES6 code accidentally by using uglify-js.

And the thing is, I don't think

warning/browser.js

Lines 21 to 22 in 0572ddd

	if (process.env.NODE_ENV !== 'production') {
	function printWarning(format, args) {

Is valid in ES5 strict mode.

[TrySound]

@gaearon I saw you committed this change here. Could you clarify on this?

[oliviertassinari]

I can reproduce the issue with Firefox 45.0.0.

[whtsky]

looks like fbjs package transpile their code before publishing to npm

> cat node_modules/fbjs/lib/warning.js
/**
 * Copyright (c) 2014-present, Facebook, Inc.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 *
 */

'use strict';

var emptyFunction = require('./emptyFunction');

/**
 * Similar to invariant but only logs a warning if the condition is not met.
 * This can be used to log issues in development environments in critical
 * paths. Removing the logging code for production environments will keep the
 * same logic and follow the same code paths.
 */

var warning = emptyFunction;

if (process.env.NODE_ENV !== 'production') {
  var printWarning = function printWarning(format) {
    for (var _len = arguments.length, args = Array(_len > 1 ? _len - 1 : 0), _key = 1; _key < _len; _key++) {
      args[_key - 1] = arguments[_key];
    }

    var argIndex = 0;
    var message = 'Warning: ' + format.replace(/%s/g, function () {
      return args[argIndex++];
    });
    if (typeof console !== 'undefined') {
      console.error(message);
    }
    try {
      // --- Welcome to debugging React ---
      // This error was thrown as a convenience so that you can use this stack
      // to find the callsite that caused this warning to fire.
      throw new Error(message);
    } catch (x) {}
  };

  warning = function warning(condition, format) {
    if (format === undefined) {
      throw new Error('`warning(condition, format, ...args)` requires a warning ' + 'message argument');
    }

    if (format.indexOf('Failed Composite propType: ') === 0) {
      return; // Ignore CompositeComponent proptype check.
    }

    if (!condition) {
      for (var _len2 = arguments.length, args = Array(_len2 > 2 ? _len2 - 2 : 0), _key2 = 2; _key2 < _len2; _key2++) {
        args[_key2 - 2] = arguments[_key2];
      }

      printWarning.apply(undefined, [format].concat(args));
    }
  };
}

module.exports = warning;