JS: String.prototype.slice

str.slice(start)

Return a substring from index start to end.

console.log("abcd".slice(1, 3) === "bc");

str.slice(start, end)

Return a substring from index start to end.

console.log("abcd".slice(0, "abcd".length) === "abcd");
console.log("abcd".slice() === "abcd");
console.log("abcd".slice(1) === "bcd");
console.log("abcd".slice(-1) === "d");
console.log("abcd".slice(-2) === "cd");

// same index, empty string
console.log("abcd".slice(2, 2) === "");

// when start index is greater than end index, result is empty string
console.log("abcd".slice(3, 2) === "");
console.log("abcd".slice(-2, -3) === "");

// all true

🛑 WARNING: "😂".length === 2 〔see JS: String Code Unit〕