[Javascript] Compare a Generator to Using Array Map and Filter

Generators offer flexible alternatives to working with arrays and how you want to iterate through the data. While most scenarios are covered by the methods included on Arrays such as "map" and "filter", generators are great for covering complex scenarios when writing all your logic in map and filter functions might become difficult.

let names = ["John", "Mindy", "Sally"]

let result = names.filter(name => name.includes("y")).map(name => name.toLocaleLowerCase())
console.log(result) // ["mindy", "sally"]

// -- Generator --

function* format(array: string[]) {
    for (let name of array) {
        if (name.includes("y")) {
            yield name.toLowerCase();
        }
    }
}

console.log([...format(names)]); //["mindy", "sally"]

With Generator, we can do more control on result.

let names = ["John", "Mindy", "Sally"]

let result = names.filter(name => name.includes("y")).map(name => name.toLocaleLowerCase())
console.log(result) // ["mindy", "sally"]

// -- Generator --

function* format(array: string[]) {
    for (let name of array) {
        if (name.includes("y")) {
            yield name.toLowerCase(); // ["mindy", "sally"]
            yield name.toUpperCase(); // ["mindy", "MINDY", "sally", "SALLY"]
            yield* array; // ["mindy", "MINDY", "John", "Mindy", "Sally", "sally", "SALLY", "John", "Mindy", "Sally"]
            yield 'END'; // ["mindy", "MINDY", "John", "Mindy", "Sally", "END", "sally", "SALLY", "John", "Mindy", "Sally", "END"]
        }
    }
}

console.log([...format(names)]);