一些有趣的js编程技巧

findSum

Given an unordered array of integers and a value sum, return true if any two items may be added such that they equal the value of sum . Otherwise, return false.


const findSum = (arr, val) => {
  let searchValues = new Set();
  searchValues.add(val - arr[0]);
  for (let i = 1, length = arr.length; i < length; i++) {
    let searchVal = val - arr[i];
    if (searchValues.has(arr[i])) {
      return true;
    } else {
      searchValues.add(searchVal);
    }
  };
  return false;
};

awesome way

1	const findSum = (arr, sum) => arr.some(set => n => set.has(n) \|\| !set.add(sum - n)(new Set);

Method Parameter Validation

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const isRequired = () => {  throw new Error('param is requied') };

const print = (num = isRequired()) => console.log(num);

Format JSON Code

1	JSON.stringify({"name": "Jack"}, null '\t');