Why I can not start harmony mode by “node --harmony test.js” from command line?

问题

The problem is：

longhao33@hePC:~$ node --harmony test.js 
/home/longhao33/test.js:1
(function (exports, require, module, __filename, __dirname) { let str = 'es666666666666';
                                                              ^^^

SyntaxError: Block-scoped declarations (let, const, function, class) not yet supported outside strict mode
    at exports.runInThisContext (vm.js:53:16)
    at Module._compile (module.js:413:25)
    at Object.Module._extensions..js (module.js:452:10)
    at Module.load (module.js:355:32)
    at Function.Module._load (module.js:310:12)
    at Function.Module.runMain (module.js:475:10)
    at startup (node.js:117:18)
    at node.js:951:3

But "let" is supported when:（So strange！）

longhao33@hePC:~$ node --harmony
> let str = 'es66666666666'
undefined
> str
'es66666666666'

1. system:ubuntu 14.04LTS 64bit
2. node:V4.1.1 (Installed by nvm,which is installed at $HOME)

3. content of test.js:

   let str = 'es666666666666'; console.log(str);

Thanks ahead of time.

回答1:

You're missing 'use strict'; at the top of your test.js (as indicated by the error message).

It works in the REPL because 'use strict'; is automatically included during code evaluation.

来源：https://stackoverflow.com/questions/32891755/why-i-can-not-start-harmony-mode-by-node-harmony-test-js-from-command-line