Check if an array contains part of a string and find the index number

Question

const myArr = [ "blue", "red", "orange", "green" ];

I was wondering how to check if an array contains part of a string and the index number of the matching string.

I’ve seen this online but the index number doesn’t show the position unless it’s the full name in the array.

myArr.indexOf("oran")

Answer 1

You can use some to check if there's at least one element verifying your condition :

var hasSome = myArr.some(function(v){ return v.indexOf("oran")>=0 })

If you need the index, a reverse for loop is the simpler solution :

for (var i=myArr.length; i--;) {
     if (myArr[i].indexOf("oran")>=0) break;
}

After the loop, i is -1 if no element matches, it's its index if one matches.

Note that in ES6 (the next version of JavaScript), you'll have the find and findIndex methods on arrays and the includes method on strings, which means you'll be able to do

var i = myArr.findIndex(v => v.includes("oran"));