@rbxts/jsnatives

slice

Extracts a section of a string and returns it as a new string.

Signature

function slice(str: string, start?: NumericAdmissible, end?: NumericAdmissible): string

Description

The slice function extracts a section of a string and returns it as a new string, without modifying the original string. The extracted portion starts at the start index and ends at, but does not include, the end index.

Parameters

str: The string to extract from.
start (optional): The zero-based index at which to begin extraction. If a string is provided, it will be converted to a number. If omitted, extraction starts from the beginning of the string (index 0).
end (optional): The zero-based index before which to end extraction. If a string is provided, it will be converted to a number. If omitted, extraction continues to the end of the string.

Return value

A new string containing the extracted section of the string.

Examples

Basic usage

// Extract a substring
const str = "Hello world";
const world = String.slice(str, 6);
print(world); // Outputs: "world"

const hello = String.slice(str, 0, 5);
print(hello); // Outputs: "Hello"

Using negative indices

// Negative indices count from the end of the string
const str = "Hello world";
const last5 = String.slice(str, -5);
print(last5); // Outputs: "world"

const excludeLast = String.slice(str, 0, -1);
print(excludeLast); // Outputs: "Hello worl"

Using string indices

// String indices are converted to numbers
const str = "Hello world";
const portion = String.slice(str, "1", "5");
print(portion); // Outputs: "ello"

Edge cases

const str = "Hello world";

// If start > end, an empty string is returned
const emptyResult = String.slice(str, 5, 2);
print(emptyResult); // Outputs: "" (empty string)

// If start > string length, an empty string is returned
const beyondLength = String.slice(str, 20);
print(beyondLength); // Outputs: "" (empty string)

// If end > string length, extraction continues to the end
const toEnd = String.slice(str, 6, 100);
print(toEnd); // Outputs: "world"

Using without parameters

// Without parameters, the entire string is returned
const str = "Hello world";
const copy = String.slice(str);
print(copy); // Outputs: "Hello world"

Common slicing patterns

const str = "Hello world";

// Get first 5 characters
const first5 = String.slice(str, 0, 5);
print(first5); // Outputs: "Hello"

// Get last 5 characters
const last5 = String.slice(str, -5);
print(last5); // Outputs: "world"

// Remove first character
const withoutFirst = String.slice(str, 1);
print(withoutFirst); // Outputs: "ello world"

// Remove last character
const withoutLast = String.slice(str, 0, -1);
print(withoutLast); // Outputs: "Hello worl"