Javascript Substring Method

Substring is a built-in method of javascript that extract a specific part of a string. We can pass two parameters to this method. The first parameter is compulsory while the second one is not.

Syntax: substring(startIndex) Or substring(startIndex, endIndex).

If we pass only the first parameter then it will extract the substring from the given index to the end of the actual string.

Example

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const myString = 'Hello world!';
// Output: "lo world!"
console.log(myString.substring(3));

If we pass all parameters(two) then it will extract only the substring between them but keep in mind the last index will not be included.

Example

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const myString = 'Hello world!';
// Output: "world"
console.log(myString.substring(6, 11));

If the start index is greater than the end index then it will swap e.g substring(3, 1) will be equal to substring(1, 3).
If the start index or end index is less than 0 then it will consider 0.