javascript 按第一个长度分割字符串

Question

I have a string like this "1a8abder412183a2b9654123879"

How can I split the string by length of first char like this using javascript

1 -> a,
8 -> abder412,
3 -> a2b,
9 -> 654123879,

Answer 1

Assuming only length of 1 to 9, then you could get the length from the actual index and slice the array by taking the index plus expected length. Proceed until no more string si left.

 var string = '1a8abder412183a2b9654123879', result = [], index = 0, length; while (index < string.length) result.push([length = +string[index++], string.slice(index, index += length)]); console.log(result);

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Answer 2

 let input = '1a8abder412183a2b9654123879'; let keys = [1, 8, 3, 9]; let splitByKeys = (input, keys) => { let lastIndex = input.indexOf(keys[0]); let splits = []; for (let i = 1; i <= keys.length; i++) { let index = i < keys.length? input.indexOf(keys[i], lastIndex): input.length; let m = input.substring(lastIndex + 1, index); lastIndex = index; splits.push([keys[i - 1], m]); } return Object.fromEntries(splits); } let output = splitByKeys(input, keys); console.log(output);

Answer 3

 const str = "1a8abder412183a2b9654123879"; const chunks = (arr, acc = []) => { return (arr.length === 0)? acc: chunks( arr.slice(parseInt(arr[0])+1), [...acc, arr.slice(0, parseInt(arr[0]) + 1).join('')] ); } console.log(chunks([...str]));