Get factorial of a given number using memoization techniques.
Previously we have seen how memoization can be used in a reusable function to get all the advantages of memoization, without the complexity.
Today, let us see one more practical example - get factorial of a given number.
First, create a function to calculate factorial.
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let factorial = function(n) {
return n <= 1 ? 1 : n * factorial(n - 1);
};
console.log(factorial(5));
// 120. works!
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Then, wrap the factorial function in memoThis.
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let memoThis = function(func) {
const cache = {};
return (...args) => {
const key = JSON.stringify(args);
return key in cache ? cache[key] : (cache[key] = func(...args));
};
};
let factorial = memoThis(function(n) {
return n <= 1 ? 1 : n * factorial(n - 1);
});
console.log(factorial(5));
// 120
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