How to fix Could not find a declaration file for module 'lodash' in TypeScript

# Using npm
npm install --save-dev @types/lodash

# Using yarn
yarn add --dev @types/lodash

# Using pnpm
pnpm add -D @types/lodash

// This will now have full type support
import _ from "lodash";
import { debounce, groupBy } from "lodash";

const numbers = [1, 2, 3, 4];
const doubled = _.map(numbers, n => n * 2);  // Type: number[]

# Verify the package exists
npm list @types/lodash

# Check node_modules structure
ls -la node_modules/@types/lodash

# View package.json to confirm it's listed
cat package.json | grep "@types/lodash"

└── @types/[email protected]

# For npm workspaces
npm install --workspace=packages/my-app --save-dev @types/lodash

# For yarn workspaces (install from the specific workspace directory)
cd packages/my-app && yarn add --dev @types/lodash

{
  "compilerOptions": {
    "typeRoots": [
      "./node_modules/@types"
    ],
    "types": [],  // Empty array means include all @types packages
    "moduleResolution": "node",
    "esModuleInterop": true
  }
}

{
  "compilerOptions": {
    "typeRoots": [
      "./node_modules/@types",
      "./custom-types"  // Any additional custom type directories
    ]
  }
}

{
  "compilerOptions": {
    // WRONG - this excludes lodash types
    "types": ["node", "jest"]

    // CORRECT - include lodash explicitly if using types field
    "types": ["node", "jest", "lodash"]
  }
}

npm install --save-dev @types/lodash-es

// For lodash (CommonJS)
import _ from "lodash";
import { debounce } from "lodash";  // Types from @types/lodash

// For lodash-es (ES Modules)
import _ from "lodash-es";
import { debounce } from "lodash-es";  // Types from @types/lodash-es

# Remove node_modules and lock files
rm -rf node_modules
rm package-lock.json  # or yarn.lock / pnpm-lock.yaml

# Clear package manager cache
npm cache clean --force
# or
yarn cache clean
# or
pnpm store prune

# Reinstall all dependencies
npm install

# Restart dev server
npm run dev

# In VS Code, restart TypeScript
# Cmd/Ctrl + Shift + P → "TypeScript: Restart TS Server"

// types/lodash.d.ts
declare module "lodash" {
  const _: any;
  export = _;
}

// Or with basic types:
declare module "lodash" {
  export function map<T, U>(
    collection: T[],
    iteratee: (value: T) => U
  ): U[];

  export function debounce<T extends (...args: any[]) => any>(
    func: T,
    wait?: number
  ): T;

  // Add other functions you use...
}

{
  "include": [
    "src/**/*",
    "types/**/*"
  ]
}