string-dedent

De-indents (dedents) passed in strings

Removes the leading whitespace from each line, allowing you to break the string into multiple lines with indentation. If lines have an uneven amount of indentation, then only the common whitespace is removed.

The opening and closing lines (which contain the ` marks) must be on their own line. The opening line must be empty, and the closing line may contain whitespace. The opening and closing line will be removed from the output, so that only the content in between remains.

1const dedent = require('string-dedent');
2
3function example() {
4  console.log('Outputs:');
5  console.log(dedent`
6    This line will appear without any indentation.
7      * This list will appear with 2 spaces more than previous line.
8      * As will this line.
9
10    Empty lines (like the one above) will not affect the common indentation.
11  `);
12}
13example();

1Outputs:
2This line will appear without any indentation.
3  * This list will appear with 2 spaces more than previous line.
4  * As will this line.
5
6Empty lines (like the one above) will not affect the common indentation.

Installation

1npm install string-dedent

Usage

The most common way to dedent is to use it as a tagged template literal. It supports expression interpolation, where the expressions will not affect the dedenting:

1const exp = 'expressions';
2const threeSpaces = '   ';
3console.log('Outputs:');
4console.log(dedent`
5  This supports ${exp} as you would expect.
6
7  Only whitespace that appears here inside the tagged template literal
8  will be dedented.
9  ${threeSpaces}<- expression whitespace will not be removed
10`);
11
12/*
13Outputs:
14This supports expressions as you would expect.
15
16Only whitespace that appears here inside the tagged template literal
17will be dedented.
18   <- expression whitespace will not be removed
19*/

If you need to use a tagged template literal like html, you can wrap the tag with dedent:

1// Regular html usage:
2const html = require('lit-html');
3render(container, html`
4  <div>The leading whitespace before this div tag will create a Text node in the output...</div>
5`);
6
7// Wrapped html usage:
8const html = dedent(require('lit-html'));
9render(container, html`
10  <div>Leading whitespace before this div tag will not make it to HTML</div>
11`);

Additionally, you may also call it like a function. This allows you to interpolate expressions into your string, and have the full string dedented.

1const threeSpaces = '   ';
2const str = `
3  Used as a function
4${threeSpaces}<- expression whitespace will be removed
5`;
6console.log('Outputs:');
7console.log(dedent(str));
8
9/*
10Outputs:
11Used as a function
12 <- expression whitespace will be removed
13*/