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.

If the first or last lines contain only whitespace, they will be removed entirely. This allows the opening and closing ` mark to be on their own line.

const dedent = require('string-dedent');

function example() {
  console.log('Outputs:');
  console.log(dedent`
    This line will appear without any indentation.
      * This list will appear with 2 spaces more than previous line.
      * As will this line.

    Empty lines (like the one above) will not affect the common indentation.
  `);
}
example();

Outputs:
This line will appear without any indentation.
  * This list will appear with 2 spaces more than previous line.
  * As will this line.

Empty lines (like the one above) will not affect the common indentation.

Installation

npm 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:

const exp = 'expressions';
const threeSpaces = '   ';
console.log('Outputs:');
console.log(dedent`
  This supports ${exp} as you would expect.

  Only whitespace that appears here inside the tagged template literal
  will be dedented.
  ${threeSpaces}<- expression whitespace will not be removed
`);

/*
Outputs:
This supports expressions as you would expect.

Only whitespace that appears here inside the tagged template literal
will be dedented.
   <- expression whitespace will not be removed
*/

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

// Regular html usage:
const html = require('lit-html');
render(container, html`
  <div>The leading whitespace before this div tag will create a Text node in the output...</div>
`);

// Wrapped html usage:
const html = dedent(require('lit-html'));
render(container, html`
  <div>Leading whitespace before this div tag will not make it to HTML</div>
`);

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

const threeSpaces = '   ';
const str = `
  Used as a function
${threeSpaces}<- expression whitespace will be removed
`;
console.log('Outputs:');
console.log(dedent(str));

/*
Outputs:
Used as a function
 <- expression whitespace will be removed
*/