Sword finger offer 05 Replace spaces

One algorithm a day ~~, Stick to the first day .

Please implement a function , Put the string s Replace each space in with "%20".
Range ：0 <= s The length of <= 10000

Example ：

	 Input ：s = "We are happy."
	 Output ："We%20are%20happy."	

How to solve the problem 1：
Ideas ： Simple and rough direct use split Method , Separate them into string arrays with spaces , And then use join Method is then converted to a string .

	function replaceSpace(s){
    
		if(s.length > 10000) return null;
		return s.split(" ").join("%20");
	}

How to solve the problem 2：
Ideas ： Replace with regular expressions

	function replaceSpace(s){
    
		if(s.length > 10000) return null;
		return s.replace(/ /g, '%20')
	}

How to solve the problem 3：
Ideas ： Loop string , Then determine whether there is a blank space , If there are spaces, replace them with

	function replaceSpace(s){
    
	    if(s.length > 10000) return null;
    	let str = ''
    	for (const key in s) {
    
        	if(s[key] === ' '){
    
            	str = str + '%20'
        	}else{
    
            	str = str + s[key]
        	}
    	}
    	return str;
    }

Now think of these methods . If there is still a good way , I hope you can share more .

Code Not just for young people , It should be a lifelong hobby ~