javascript Archives - Page 255 of 258

How can I check if an object is an array? [duplicate]

This question already has answers here: How do you check if a variable is an array in JavaScript? (24 answers) Closed 6 months ...

April 10, 2022
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What is the difference between call and apply?

What is the difference between using Function.prototype.apply() and Function.prototype.call() to invoke a function? var func = function() { alert('hello!'); }; func.apply(); vs func.call(); ...

April 10, 2022
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How do I loop through or enumerate a JavaScript object?

I have a JavaScript object like the following: var p = { "p1": "value1", "p2": "value2", "p3": "value3" }; Now I want to ...

April 10, 2022
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How do I correctly clone a JavaScript object?

I have an object x. I’d like to copy it as object y, such that changes to y do not modify x. I ...

April 9, 2022
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How can I check for an empty/undefined/null string in JavaScript?

I saw this question, but I didn’t see a JavaScript specific example. Is there a simple string.Empty available in JavaScript, or is it ...

April 9, 2022
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How to round to at most 2 decimal places, if necessary?

I’d like to round at most 2 decimal places, but only if necessary. Input: 10 1.7777777 9.1 Output: 10 1.78 9.1 How can ...

April 9, 2022
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Sort array of objects by string property value

I have an array of JavaScript objects: var objs =...

April 9, 2022
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Checking if a key exists in a JavaScript object?

How do I check if a particular key exists in a JavaScript object or array? If a key doesn’t exist, and I try ...

April 9, 2022
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Loop through an array in JavaScript

In Java you can use a for loop to traverse objects in an array as follows: String...

April 9, 2022
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How to insert an item into an array at a specific index (JavaScript)

I am looking for a JavaScript array insert method, in the style of: arr.insert(index, item) Preferably in jQuery, but any JavaScript implementation will ...

April 9, 2022
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