TypeScript Dedent

Common errors

• TypeError: (0 , ts_dedent_1.default) is not a function

  cause Attempting to use `dedent` as a named import (e.g., `import { dedent } from 'ts-dedent';`) when it's exported as a default.
  fix Change the import statement to `import dedent from 'ts-dedent';`.

• TypeError: require(...) is not a function

  cause Attempting to use CommonJS `require('ts-dedent')` directly without accessing the default export.
  fix Modify the require statement to `const dedent = require('ts-dedent').default;`.

• My string has extra unwanted indentation after upgrading!

  cause Upgrading to v2.0.0 changed how `ts-dedent` handles lines not starting with whitespace, causing previous assumptions about indentation removal to be incorrect.
  fix Review affected template literals. If a line should have its indentation removed, ensure it starts with whitespace, or adjust your expected output.

Warnings

• breaking Version 2.0.0 introduced a breaking change regarding indentation removal logic. Previously, indentation was always removed. Now, if a line does not start with whitespace, its indentation will not be removed.
  Fix: Review existing template literals, especially those where the first character of a line might not be whitespace, to ensure desired indentation is preserved or adjusted.
• gotcha The README examples incorrectly show `import dedent from 'dedent';`. This refers to a *different* npm package. For `ts-dedent`, you *must* import from `'ts-dedent'`.
  Fix: Always use `import dedent from 'ts-dedent';` for ESM or `const dedent = require('ts-dedent').default;` for CommonJS.
• deprecated Older versions (prior to 2.2.0) had less robust ESM support. While CJS was always supported, the introduction of a dedicated ESM module in v2.2.0 improved compatibility.
  Fix: Upgrade to v2.2.0 or newer for the best ESM compatibility and features, including indentation of multiline string values within template literals.
• gotcha Starting with v2.2.0, `ts-dedent` adds indentation to values that contain multiline strings. This might subtly change output if your placeholders previously contained un-indented multi-line strings.
  Fix: Test output with multi-line string placeholders after upgrading to v2.2.0 to ensure the new indentation behavior aligns with expectations.

Install

• npm install ts-dedent npm
• yarn add ts-dedent yarn
• pnpm add ts-dedent pnpm

Imports

• dedent
  wrong:

  import { dedent } from 'ts-dedent';

  correct:

  import dedent from 'ts-dedent';

  The `dedent` function is exported as the default export of the 'ts-dedent' package. Do not use named import syntax.
• dedent
  wrong:

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

  correct:

  const dedent = require('ts-dedent').default;

  For CommonJS, access the default export via `.default`.
• dedent
  wrong:

  import dedent from 'dedent';

  correct:

  import dedent from 'ts-dedent';

  Ensure you are importing from 'ts-dedent' (this package), not 'dedent' (a different, unrelated package). The README example is misleading.

Quickstart

Demonstrates `ts-dedent` usage as a template tag and a function, showing how it intelligently removes common indentation and handles placeholders in multi-line strings.

import dedent from 'ts-dedent';

// Example 1: Basic dedentation
console.log(dedent`
  A string that gets so long you need to break it over
  multiple lines. Luckily dedent is here to keep it
  readable without lots of spaces ending up in the string
  itself.
`);

// Example 2: Dedentation with nested indents and placeholders
const user = 'Alice';
const items = ['apple', 'banana', 'cherry'];
console.log(dedent`
  Hello, ${user}!
  Here is your shopping list:

    * ${items[0]}
    * ${items[1]}
    * ${items[2]}

  Thank you.
`);

// Example 3: Using dedent as a function
const multilineString = dedent(`
  This also works perfectly
  fine as a regular function call.
`);
console.log(multilineString);