Linked Questions

4 votes

0 answers

98 views

Array function could called as a function like Array() or as constructor new Array(). Is there any difference between these 2 calling method?

1 vote

0 answers

78 views

Usage of the var myArray = Array(10).fill(0); and var myArray = new Array(10).fill(0); seemingly return the same result. Are there any differences between these two expressions? When should you use ...

-3 votes

2 answers

83 views

Array(3), result: { length: 3__proto__: Array(0) } There is no index 0, 1, 2... But Array.call(null, Array(3)) has, { 0: undefined, 1: undefined, 2: undefined, length: 3, __proto__: Array(0) } I ...

-1 votes

1 answer

67 views

Why are these two statements the same in JavaScript? var a = new Array(5); var a = Array(5); Or, if they are not the same, what is different about them? Basically if I assign a to a different ...

1412 votes

56 answers

2.9m views

I have been reading online and some places say it isn't possible, some say it is and then give an example and others refute the example, etc. How do I declare a 2 dimensional array in JavaScript? (...

886 votes

46 answers

691k views

What is the most efficient way to create an arbitrary length zero filled array in JavaScript?

970 votes

20 answers

940k views

What's the real difference between declaring an array like this: var myArray = new Array(); and var myArray = [];

597 votes

13 answers

123k views

In another question, a user pointed out that the new keyword was dangerous to use and proposed a solution to object creation that did not use new. I didn't believe that was true, mostly because I've ...

212 votes

6 answers

421k views

I'm having trouble either declaring or using a boolean array in Typescript, not sure which is wrong. I get an undefined error. Am I supposed to use JavaScript syntax or declare a new Array object? ...

19 votes

6 answers

25k views

In python you can do: arr = [1,2,3] * 3 print(arr) output: [1,2,3,1,2,3,1,2,3] Is there a concise way of doing this in java script? The best I can think of is something like: let arr2 = [...arr, ......

1 vote

0 answers

252 views

What is the difference between these two way of initializing an array in modern javascript environment (in ES6 spec) ? const arr1 = new Array(3); const arr2 = Array(3); They look same running in ...

1 vote

3 answers

122 views

What the different if both of them call the constructor "Array" and generate an object? I know that we lost this if we create some object without new: function Animal(name) {this.name = name} var ...

1 vote

1 answer

78 views

I've been playing around with generating image filters using canvas, and I was attempting to improve speed by preallocating an entire matrix from the beginning. This code was the first thing that I ...

0 votes

2 answers

82 views

function Person(name, age, gender) { this.name = name; // run } function PersonSafe(name) { if (!(this instanceof arguments.callee)) return new PersonSafe(name) this.name = name; //...