JS: Extract portion of a string using substr() and substring()

tkeeching — Wed, 07 Oct 2020 06:09:26 +0000

In JavaScript, there are two string methods that let us extract a portion of a string with ease.

The first method substr allows us to specify the number of characters from the start position that we wish to extract.

const sampleStr = "+11";
const count1 = sampleStr.substr(1, 1); // 1
const count2 = sampleStr.substr(1, 2); // 11

The second method substring allows us to specify the start (inclusive) and end (not inclusive) position of the characters we wish to extract.

const sampleStr = "+1024";
const count1 = sampleStr.substring(1, 2); // 1
const count2 = sampleStr.substring(1, 3); // 10

However, if we do not specify the second parameters in both methods, it will extract the remaining of the string.

const sampleStr = "+1024";
const count1 = sampleStr.substr(1); // 1024
const count2 = sampleStr.substring(2); // 024

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