This TypeScript error occurs when you have conflicting compiler options in your tsconfig.json file. The 'strict' option already includes 'noImplicitAny', so specifying both creates a redundancy conflict. The fix involves removing the redundant 'noImplicitAny' option or using 'strict' alone for comprehensive type safety.
TypeScript's compiler options are designed to enforce type safety at different levels. The `strict` option is a convenient shorthand that enables a comprehensive set of strict type-checking behaviors, including: - **noImplicitAny**: Requires explicit type annotations for `any` types - **noImplicitThis**: Checks `this` parameter in functions - **strictNullChecks**: Requires handling of `null` and `undefined` - **strictFunctionTypes**: Enforces stricter function type checking - **strictBindCallApply**: Strict checking of `bind`, `call`, and `apply` methods - **strictPropertyInitialization**: Ensures class properties are initialized When you set `"strict": true` in your tsconfig.json, TypeScript automatically enables all these strict mode options. If you then also explicitly set `"noImplicitAny": true` (or `false`), you're creating a conflict because: 1. `strict: true` already implies `noImplicitAny: true` 2. TypeScript cannot determine which setting should take precedence 3. The options are mutually exclusive in configuration terms This error typically appears when: - Migrating from older TypeScript versions where `noImplicitAny` was used separately - Copying configuration from multiple sources without understanding the relationships - Using IDE-generated tsconfig.json files that include redundant options - Extending base configurations that already have `strict: true`
Open your tsconfig.json and look for both 'strict' and 'noImplicitAny':
WRONG - Causes conflict:
{
"compilerOptions": {
"strict": true,
"noImplicitAny": true // Redundant - already included in strict!
}
}WRONG - Also causes conflict:
{
"compilerOptions": {
"strict": true,
"noImplicitAny": false // Contradicts strict!
}
}CORRECT - Use strict alone:
{
"compilerOptions": {
"strict": true
// noImplicitAny is automatically true
}
}CORRECT - Use individual options (not strict):
{
"compilerOptions": {
"noImplicitAny": true,
"strictNullChecks": true,
"strictFunctionTypes": true,
// ... other individual strict options
}
}If you want comprehensive strict checking, keep 'strict': true and remove 'noImplicitAny':
{
"compilerOptions": {
"strict": true,
// Remove this line:
// "noImplicitAny": true
}
}If you need to disable noImplicitAny while keeping other strict options, you must use individual options instead:
{
"compilerOptions": {
"noImplicitAny": false,
"strictNullChecks": true,
"strictFunctionTypes": true,
"strictBindCallApply": true,
"strictPropertyInitialization": true,
"noImplicitThis": true,
"alwaysStrict": true
}
}This gives you control over each strictness option individually.
If your tsconfig extends another configuration, the conflict might come from there:
{
"extends": "./tsconfig.base.json",
"compilerOptions": {
"noImplicitAny": true // Overrides inherited strict setting
}
}Check what's in the base configuration:
# Check if base config has strict: true
cat tsconfig.base.json | grep -A5 '"compilerOptions"'If the base has "strict": true, you have two options:
1. Remove the override (use strict from base):
{
"extends": "./tsconfig.base.json"
// Don't override noImplicitAny
}2. Disable strict and use individual options:
{
"extends": "./tsconfig.base.json",
"compilerOptions": {
"strict": false, // Disable inherited strict
"noImplicitAny": true,
// Add other strict options you want
}
}In monorepos with multiple packages, ensure consistency:
Root tsconfig.json (shared settings):
{
"compilerOptions": {
"strict": true
}
}Package tsconfig.json (extends root):
{
"extends": "../../tsconfig.json",
"compilerOptions": {
// Don't add noImplicitAny here
"outDir": "./dist"
}
}If a specific package needs different strictness, create a custom config:
tsconfig.strict.json (for packages needing max strictness):
{
"extends": "../../tsconfig.json",
"compilerOptions": {
"strict": true
}
}tsconfig.loose.json (for packages needing less strictness):
{
"extends": "../../tsconfig.json",
"compilerOptions": {
"strict": false,
"noImplicitAny": false,
"strictNullChecks": false
}
}Test your configuration:
# Check for configuration errors
npx tsc --showConfig
# Run type checking
npx tsc --noEmit
# Or build if applicable
npx tscIf successful, you should:
- See no TS5053 error
- Get proper type checking based on your configuration
- Be able to compile/build without configuration errors
You can also verify which options are active:
# Create a test file to see strictness in action
echo 'function test(a) { return a; }' > test.ts
npx tsc test.ts --noEmitWith strict: true or noImplicitAny: true, this should show an error about implicit 'any'.
### Understanding the strict Option Hierarchy
TypeScript's strict option is actually a compiler flag group that enables multiple related options. When you set strict: true, TypeScript internally sets these flags:
strict: true = {
noImplicitAny: true,
noImplicitThis: true,
strictNullChecks: true,
strictFunctionTypes: true,
strictBindCallApply: true,
strictPropertyInitialization: true,
alwaysStrict: true
}### Migration from Older TypeScript Versions
If you're migrating from TypeScript <2.0, you might have used noImplicitAny separately. The strict option was introduced in TypeScript 2.0 to bundle common strictness flags.
Migration path:
1. Remove individual noImplicitAny, strictNullChecks, etc.
2. Add strict: true for comprehensive strictness
3. If you need to disable specific strictness features, use strict: false and enable only the ones you want
### IDE and Tool Integration
Some IDEs and build tools might generate tsconfig.json files with redundant options:
- VS Code: When creating tsconfig.json via command palette
- Create React App: Includes specific TypeScript configurations
- Angular CLI: Has its own TypeScript configuration patterns
- Nx/Turborepo: May generate conflicting configurations in monorepos
Always review generated configurations and remove redundancies.
### Performance Considerations
While strict: true provides maximum type safety, it can increase compilation time. If you're experiencing slow builds:
1. Use strict: true in development for safety
2. Consider strict: false in CI/CD if build time is critical
3. Use incremental compilation (incremental: true) to speed up subsequent builds
### TypeScript Version Compatibility
The exact behavior of strict has evolved:
- TypeScript 2.0: Introduced strict flag
- TypeScript 2.7: Added strictPropertyInitialization
- TypeScript 3.7: Added strictBindCallApply
Check your TypeScript version if you encounter unexpected behavior with strict options.
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