let str = 'a nice girl';
    let upperStr = str.replace(/\s+([^\s]*)/g,function($0,$1){
       return $1.substring(0,1).toUpperCase()+$1.substring(1);
    })
    console.log(upperStr()) //aNiceGirl
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    let a =  'hello world' ;
    var b=a.split(' ').map(item=>{
        return item[0].toUpperCase()+item.substr(1,item.length)
    }).join('')
    console.log(b)//helloWrold
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