35 lines
934 B
Markdown
35 lines
934 B
Markdown
---
|
|
title: Index of substrings
|
|
type: snippet
|
|
language: javascript
|
|
tags: [string,algorithm,generator]
|
|
author: chalarangelo
|
|
cover: violin
|
|
dateModified: 2020-12-31T13:58:51+02:00
|
|
---
|
|
|
|
Finds all the indexes of a substring in a given string.
|
|
|
|
- Use `Array.prototype.indexOf()` to look for `searchValue` in `str`.
|
|
- Use `yield` to return the index if the value is found and update the index, `i`.
|
|
- Use a `while` loop that will terminate the generator as soon as the value returned from `Array.prototype.indexOf()` is `-1`.
|
|
|
|
```js
|
|
const indexOfSubstrings = function* (str, searchValue) {
|
|
let i = 0;
|
|
while (true) {
|
|
const r = str.indexOf(searchValue, i);
|
|
if (r !== -1) {
|
|
yield r;
|
|
i = r + 1;
|
|
} else return;
|
|
}
|
|
};
|
|
```
|
|
|
|
```js
|
|
[...indexOfSubstrings('tiktok tok tok tik tok tik', 'tik')]; // [0, 15, 23]
|
|
[...indexOfSubstrings('tutut tut tut', 'tut')]; // [0, 2, 6, 10]
|
|
[...indexOfSubstrings('hello', 'hi')]; // []
|
|
```
|