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copied!<pre><code>var dict = []; // create an empty array dict.push({ key: "keyName", value: "the value" }); // repeat this last part as needed to add more key/value pairs </code></pre> <p>Basically, you're creating an object literal with 2 properties (called <code>key</code> and <code>value</code>) and inserting it (using <code>push()</code>) into the array.</p> <hr> <p><strong>Edit:</strong> So almost 5 years later, this answer is getting downvotes because it's not creating an "normal" JS object literal (aka map, aka hash, aka dictionary).<br> It <em>is</em> however creating the structure that OP asked for (and which is illustrated in the other question linked to), which is <em>an array of object literals</em>, each with <code>key</code> and <code>value</code> properties. Don't ask me why that structure was required, but it's the one that was asked for.</p> <p>But, but, if what you want in a plain JS object - and <em>not</em> the structure OP asked for - see <a href="https://stackoverflow.com/a/22315575/167996">tcll's answer</a>, though the bracket notation is a bit cumbersome if you just have simple keys that are valid JS names. You can just do this:</p> <pre><code>// object literal with properties var dict = { key1: "value1", key2: "value2" // etc. }; </code></pre> <p>Or use regular dot-notation to set properties after creating an object:</p> <pre><code>// empty object literal with properties added afterward var dict = {}; dict.key1 = "value1"; dict.key2 = "value2"; // etc. </code></pre> <p>You <em>do</em> want the bracket notation if you've got keys that have spaces in them, special characters, or things like that. E.g:</p> <pre><code>var dict = {}; // this obviously won't work dict.some invalid key (for multiple reasons) = "value1"; // but this will dict["some invalid key (for multiple reasons)"] = "value1"; </code></pre> <p>You also want bracket notation if your keys are dynamic:</p> <pre><code>dict[firstName + " " + lastName] = "some value"; </code></pre> <p>Note that keys (property names) are always strings, and non-string values will be coerced to a string when used as a key. E.g. a <code>Date</code> object gets converted to its string representation:</p> <pre><code>dict[new Date] = "today's value"; console.log(dict); // => { // "Sat Nov 04 2016 16:15:31 GMT-0700 (PDT)": "today's value" // } </code></pre> <p>Note however that this doesn't necessarily "just work", as many objects will have a string representation like <code>"[object Object]"</code> which doesn't make for a non-unique key. So be wary of something like:</p> <pre><code>var objA = { a: 23 }, objB = { b: 42 }; dict[objA] = "value for objA"; dict[objB] = "value for objB"; console.log(dict); // => { "[object Object]": "value for objB" } </code></pre> <p>Despite <code>objA</code> and <code>objB</code> being completely different and unique elements, they both have the same basic string representation: <code>"[object Object]"</code>.</p> <p>The reason <code>Date</code> doesn't behave like this is that the <code>Date</code> prototype has a custom <code>toString</code> method which overrides the default string representation. And you can do the same:</p> <pre><code>// a simple constructor with a toString prototypal method function Foo() { this.myRandomNumber = Math.random() * 1000 | 0; } Foo.prototype.toString = function () { return "Foo instance #" + this.myRandomNumber; }; dict[new Foo] = "some value"; console.log(dict); // => { // "Foo instance #712": "some value" // } </code></pre> <p>(Note that since the above uses a <em>random</em> number, name collisions can still occur very easily. It's just to illustrate an implementation of <code>toString</code>.)</p> <p>So when trying to use objects as keys, JS will use the object's own <code>toString</code> implementation, if any, or use the default string representation.</p>

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