將字符串中的一部分拆分，生成不帶空格的新數組（indexOf、substring、trim)

let str='I like fruits: apple, banana, grape, peach.';
let start=str.indexOf(':');
let end=str.indexOf('.',start+1);
let fruitList=str.substring(start+1,end).split(',');
console.log(fruitList);		/*[" apple", " banana", " grape", " peach"]*/

fruitList.forEach(function(element,index,array){
	array[index]=element.trim();
});

console.log(fruitList);		/*["apple", "banana", "grape", "peach"]*/