In javascript should I use const instead of var whenever possible?

Question

If creating a reference to an object, and the reference is not going to change (even though the object will), is it better to use const instead of var?

For example:

const moment = require('moment')

exports.getQuotation = function(value) {

    const quotation = {};
    quotation.value = value;
    quotation.expiryDate = moment().add(7, 'days');

    // Do some other stuff with quotation perhaps

    return quotation;

};

Answer 1

You can use const, but you have to run node on --harmony

node app.js --harmony

You also have to set "use strict", otherwise you'll have run-time execution issues:

exports.getQuotation = function(value) {
    "use strict";

    const I_AM_CONSTANT = {};
    let quotation = {};
    ...

Other than that, yes if you are running node on --harmony, semantically it makes more sense to use const for constants. For actual variables you should use let instead of var, as let only defines the variable in the scope (avoids hoisting issues)