Today I Learned - Rocky Kev

TIL making Function Factories

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TAGS: javascript closure

This is code from the MDN.

function makeAdder(x) {
  return function(y) {
    return x + y;
  };
}

var add5 = makeAdder(5);
var add10 = makeAdder(10);

console.log(add5(2));  // 7
console.log(add10(2)); // 12

The function makeAdder() is a function factory.

It creates functions that can add a specific value to their argument.

add5 becomes function add5(x = 5, y) {}
add10 becomes function add10(x = 10, y) {}

Via:
MDN Web Docs: Closures

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