How to create dynamic Map key in javascript?

Question

I have tried to create a map like example below...

var myMap= {"one": 1,"two": "two","three": 3.0};

So, I iterate them like:

for (var key in myMap) {

window.alert("myMapmap property \"" + key + "\" = " + myMap[key]);

}

If my data is dynamic... and I want to add each of them in to map... how the codes should be like? And I expect the key is not static...I mean the data taken from other source like database, that wasn't define before..

Thanks before

score 18 · Accepted Answer · answered Mar 28 '11 at 07:36

18

var dataSource = ...;
while (var o = dataSource.get()) {
     myMap[o.key] = o.value;
}

for (var key in myMap) {
     alert("key : " + key + " value : " + myMap[key]);
}

You can simply write to an object using array like syntax.

How and where you get your data is upto you.

answered Mar 28 '11 at 07:36

Raynos

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@Stephen `myMap = {}` reset it to an empty map. – Raynos Mar 29 '11 at 10:57
how can you remove a specific element? – ffleandro Jul 05 '12 at 00:11
tf is dataSource.get? Non-ECMA. – 19h May 17 '13 at 11:25
how do I check if myMap has keys or is empty? – dierre Jul 23 '13 at 21:01
@dierre `var isEmpty = Object.keys(myMap).length === 0` – Raynos Jul 24 '13 at 21:22
Tnx, although I'm thinking cycling keys could give me more compatibility. – dierre Jul 24 '13 at 21:34

score 8 · Answer 2 · answered Mar 28 '11 at 07:36

8

Dynamic values and keys can be added using this notation:

var myMap = {}; // Create empty map
myMap["some" + "dynamic" + "key"] = "some" + "dynamic" + "variable";

answered Mar 28 '11 at 07:36

David Tang

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How to create dynamic Map key in javascript?

2 Answers2