Question 50314 in Javascript Question posted in
A very good W3school tutorial can be found here.

Is there a way to reference a javascript array directly without assigning it to a var?

I’d like to do something like this to generate some text blocks with a little variety:

["GET", "POST", "PUT", "DELETE"][Math.floor(Math.random() * this.length)]

Is it possible to reference the length property without first saving the array as a var? I’d like to do this in a one line so it’s simpler to put this into string literals with minimal extra steps.

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3

Answers


  1. 0

    You can use an IIFE like this:

    let r = (e=>e[Math.random()*e.length|0])(["GET", "POST", "PUT", "DELETE"])

console.log(r)

    Note that |0 is equivalent to Math.floor() when the number is less than 2^31

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  2. 0

    The length of the array can be accessed as a property of the array literal using dot notation:

    ["GET", "POST", "PUT", "DELETE"].length;

    Hence you could generate a random element value using the following:

    console.log(["GET", "POST", "PUT", "DELETE"][Math.floor(["GET", "POST", "PUT", "DELETE"].length * Math.random())]);
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  3. 0

    There is no way to reference an array in two places without literally assigning it to a variable in at least some way.
    There is an easy way to get a random item without any variables tho

    ["GET", "POST", "PUT", "DELETE"].sort(() => Math.random() - 0.5)[0]

    as .sort() sorts depending on if result is positive or negative, and Math.random() - 0.5 is equally randomly positive or negative

    Ways with variable

    function rndItem(HERE) { return HERE[Math.floor(Math.random() * HERE.length)] }
rndItem(["GET", "POST", "PUT", "DELETE"])
/* --- --- --- */
[["GET", "POST", "PUT", "DELETE"]].map(HERE => HERE[Math.floor(Math.random() * HERE.length)])
/* --- --- --- */
Array.prototype.rand = function(){return this[Math.floor(Math.random() * this.length)]}
["GET", "POST", "PUT", "DELETE"].rand()
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