code war daily exercises

Instruction：

x Simple, given a string of words, return the length of the shortest word(s).

String will never be empty and you do not need to account for different data types.

According to the description, there is no requirement to judge whether it is empty or the data type, so I feel free to write the length of the shortest font in a paragraph

I was like this at first Written by:

1 function findShort(s){2   var arr = s.split(' ').map(function(t){return t.length});3   return Math.min.apply(null,arr);4 }

Here we mainly use the pre-ES6 code writing method. There are 4 knowledge points:

1, string.split(' ')

The split() method is used to split a string into a string array. This method is simple and easy to understand, so I won’t go into details.

2, Array.map()

The map() method creates a new array. It will call the callback function once in order for each element in the original array. The callback is executed each time The returned value forms a new array.

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3, Math.min()

The smallest number among the given values. If any parameter cannot be converted to a numeric value, NaN is returned.

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3, apply()

When calling an existing function, you can specify a this object for it. this refers to the current object, which is the object that calls this function. Using apply, you can write this method once and then inherit it in another object, without having to write the method repeatedly in the new object.

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Later I referred to other people’s solutions. There are many good people in codewar who can write the function in one line. Here is one:

1 function findShort(s){2   return Math.min(...s.split(' ').map(w=>w.length));3 }

Here we mainly apply two new knowledge points of ES6. Although I have studied ES6 before, because I have no practical experience, I will review it here:

1. (...) is the spread operator. It can replace the apply method of the array here and is used to expand the array and convert the array into parameters of the function.

// ES5的写法Math.min.apply(null, [14, 3, 77])// ES6的写法Math.min(...[14, 3, 77])// 等同于Math.min(14, 3, 77);

Reference link: Please click here

2, arrow function (=>)

var f = v => v;//等同于var f = function(v) {  return v;
};//如果箭头函数不需要参数或需要多个参数，就使用一个圆括号代表参数部分。var f = () => 5;// 等同于var f = function () { return 5 };var sum = (num1, num2) => num1 + num2;// 等同于var sum = function(num1, num2) {  return num1 + num2;
};

The arrow function makes The expression is more concise.

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Attachment: codewar-the exercise address of this exercise

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