Node.js: for each … in not working


Question

I wanted to use for each ... in with Node.js (v0.4.11).

I use it like this:

var conf = {
   index: {
      path: {
         first: "index.html",
         pattern: "index/{num}.html"
      },
      template: "index.tpl",
      limit: 8
   },
   feed: {
      path: "feed.xml",
      template: "atom.tpl",
      limit: 8
   }
}

for each (var index in conf) {
  console.log(index.path);
}

I get the following error:

        for each (var index in conf) {
     ^^^^

node.js:134
        throw e; // process.nextTick error, or 'error' event on first tick
        ^
SyntaxError: Unexpected identifier
    at Module._compile (module.js:397:25)
    at Object..js (module.js:408:10)
    at Module.load (module.js:334:31)
    at Function._load (module.js:293:12)
    at require (module.js:346:19)
    at Object.<anonymous> (/home/paul/dev/indexing/lib/Index.js:3:13)
    at Module._compile (module.js:402:26)
    at Object..js (module.js:408:10)
    at Module.load (module.js:334:31)
    at Function._load (module.js:293:12)

Where is the mistake? for each ... in is supported since Javascript 1.6.

See MDN for information about the usage of for each ... in.

1
59
5/19/2016 3:05:33 AM

Accepted Answer

Unfortunately node does not support for each ... in, even though it is specified in JavaScript 1.6. Chrome uses the same JavaScript engine and is reported as having a similar shortcoming.

You'll have to settle for array.forEach(function(item) { /* etc etc */ }).

EDIT: From Google's official V8 website:

V8 implements ECMAScript as specified in ECMA-262.

On the same MDN website where it says that for each ...in is in JavaScript 1.6, it says that it is not in any ECMA version - hence, presumably, its absence from Node.

119
5/23/2017 12:25:48 PM

for (var i in conf) {
  val = conf[i];
  console.log(val.path);
}

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