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Ilya Kantor 2019-04-20 12:33:05 +03:00
parent 79f0463dc4
commit 069795438d

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@ -65,18 +65,18 @@ From here on the color scheme is:
````smart header="When to use `new RegExp`?" ````smart header="When to use `new RegExp`?"
Normally we use the short syntax `/.../`. But it does not allow any variable insertions, so we must know the exact regexp at the time of writing the code. Normally we use the short syntax `/.../`. But it does not support variable insertions `${...}`.
On the other hand, `new RegExp` allows to construct a pattern dynamically from a string. On the other hand, `new RegExp` allows to construct a pattern dynamically from a string, so it's more flexible.
So we can figure out what we need to search and create `new RegExp` from it: Here's an example of a dynamically generated regexp:
```js run ```js run
let search = prompt("What you want to search?", "love"); let tag = prompt("Which tag you want to search?", "h2");
let regexp = new RegExp(search); let regexp = new RegExp(`<${tag}>`);
// find whatever the user wants // finds <h2> by default
alert( "I love JavaScript".search(regexp)); alert( "<h1> <h2> <h3>".search(regexp));
``` ```
```` ````