如何遍历字符串，每次向数组添加1个额外的字符

Question

I'm trying to use JS to loop through a string value while adding the first character and the following characters to an array. This process repeats again with the next character.

For example, if I were to input ABCD then the array would turn out to be:

[A, AB, ABC, ABCD, B, BC, BCD, C, CD, D]

Answer 1

This will work:

 var str = 'ABCD' var arr = [] for (var j = 0; j < str.length; j++) { for (var i = 0; i < str.length - j; i++) { arr.push(str.substr(j, i+1)) } } console.log(arr) 

Answer 2

you can split your problem into two small function first function combination of a single word then pass this function for every element in a single world an play with the substring params.

 const text = "ABCD"; const arrayOfCombination = []; const combinationWord = word => [...word].map((el, index) => word.substring(0, index + 1)); [...text].forEach((el, index) => arrayOfCombination.push(combinationWord(text.substring(index, text.length)))); console.log(arrayOfCombination.flat())