Question

38

Node.js variable declaration and scope

rated 0 times [ 45] [ 7] / answers: 1 / hits: 95260 / 11 Years ago, fri, november 8, 2013, 12:00:00

When I type this in node.js, I get undefined.

var testContext = 15;

function testFunction() {

  console.log(this.testContext);

}

testFunction();

=>undefined

Without var keyword, it passes (=>15). It's working in the Chrome console (with and without var keyword).

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answered 11 Years ago meliashelbief · Accepted Answer

It doesn't work in Node when using var because testContext is a local of the current module. You should reference it directly: console.log(testContext);.

When you don't type var, what happens is that testContext is now a global var in the entire Node process.

In Chrome (or any other browser - well, I'm unsure about oldIE...), it doesn't matter if you use var or not in your example, testContext will go to the global context, which is window.

By the way, the global context is the default this of function calls in JS.