Webpack Loaders: Fixing "TypeError: this.getOptions is not a function"

Problem Statement

The "TypeError: this.getOptions is not a function" error is a common Webpack compatibility issue that occurs when using incompatible versions of loaders (such as sass-loader, less-loader, or css-loader) with Webpack 4. This error typically appears after updating packages or setting up a new project with conflicting dependencies.

The error message usually appears in the console with a stack trace pointing to specific loaders in your build chain:

Syntax Error: TypeError: this.getOptions is not a function

This error occurs because newer versions of many Webpack loaders (v11+ for sass-loader, v8+ for less-loader, v6+ for css-loader) are designed specifically for Webpack 5 and are not backward compatible with Webpack 4, which is still used by Vue CLI 4 and many existing projects.

Root Cause

The core issue is version incompatibility between your Webpack version and the loaders you're using:

Solutions

1. Downgrade Loaders to Webpack 4 Compatible Versions

The most reliable solution for Vue CLI 4 projects (which use Webpack 4) is to install loader versions that are compatible with Webpack 4:

npm

npm install -D sass-loader@^10 sass
npm install -D less-loader@^7
npm install -D css-loader@^5

yarn

yarn add -D sass-loader@^10 sass
yarn add -D less-loader@^7
yarn add -D css-loader@^5

2. Update package.json Dependencies

Modify your package.json to specify compatible versions:

{
  "devDependencies": {
    "sass-loader": "^10.0.0",
    "sass": "^1.32.0",
    "less-loader": "^7.3.0",
    "css-loader": "^5.2.0",
    "style-loader": "^2.0.0",
    "postcss-loader": "^4.2.0"
  }
}

3. Clean Installation

After modifying your dependencies, perform a clean installation:

npm

rm -rf node_modules
npm install

yarn

rm -rf node_modules
yarn install

4. Check for Nested Dependency Conflicts

Sometimes, sub-dependencies might install incompatible loader versions. Check for nested node_modules folders that might contain conflicting versions:

find . -name "node_modules" -type d

Remove any problematic nested dependencies, particularly within other packages' node_modules folders.

Complete Working Configuration

Here's a tested configuration that works with Vue CLI 4 and Webpack 4:

{
  "devDependencies": {
    "@vue/cli-plugin-babel": "~4.5.0",
    "@vue/cli-plugin-eslint": "~4.5.0",
    "@vue/cli-service": "~4.5.0",
    "sass": "^1.32.6",
    "sass-loader": "^10.1.1",
    "css-loader": "^5.2.0",
    "style-loader": "^2.0.0",
    "postcss-loader": "^4.2.0"
  }
}

Migration to Webpack 5

If you want to use the latest loader versions, consider upgrading to Webpack 5:

WARNING

Before upgrading, check that all your plugins and loaders are compatible with Webpack 5, as this is a major version change that may introduce breaking changes.

npm install webpack@^5.0.0

After upgrading Webpack, you can use the latest loader versions:

npm install -D sass-loader@latest less-loader@latest css-loader@latest

Preventing Future Issues

To avoid similar issues in the future:

1. Check compatibility before updating loaders
2. Pin versions in your package.json rather than using caret (^) or tilde (~) ranges
3. Review release notes for breaking changes when updating packages
4. Use consistent versions across your entire dependency tree

TIP

When creating new projects with Vue CLI, consider using Vue CLI 5 (when stable) or Vite, which use Webpack 5 or esbuild respectively, for better compatibility with newer loader versions.

Conclusion

The "TypeError: this.getOptions is not a function" error is consistently resolved by ensuring compatibility between your Webpack version and loaders. For Webpack 4 projects, downgrading to sass-loader@^10, less-loader@^7, and css-loader@^5 provides a reliable solution. Always verify your specific Webpack version and consult loader documentation for compatibility information before updating packages.