What is the process for turning off a TypeScript rule for a single line of code?

Question

What is the process for turning off a TypeScript rule for a single line of code?

Dealing with Summernote as a jQuery plugin has been a bit of a struggle for me. I'm trying to modify the object without needing type definitions, but TypeScript keeps throwing errors my way. Even after attempting to delete certain keys, I still get the dreaded error message: "Property 'summernote' does not exist on type 'jQueryStatic'."

(function ($) {

  /* tslint:disable */
  delete $.summernote.options.keyMap.pc.TAB;
  delete $.summernote.options.keyMap.mac.TAB;
  /* tslint:enable */

})(jQuery)

Edit:

Let's take a look at my tsconfig.json

{
  "compilerOptions": {
    "outDir": "./dist/",
    "sourceMap": true,
    "noImplicitAny": true,
    "module": "commonjs",
    "target": "es5",
    "allowJs": true,
    "noUnusedParameters": true
  },
  "include": [
      "js/**/*"
  ],
  "exclude": [
      "node_modules",
      "**/*.spec.ts"
  ]
}

javascript jquery typescript summernote

Answer 1

Answer №1

If you're using Typescript 2.6 or later, there's a new feature that allows you to ignore a compiler error or warning for a specific line of code:

if (false) {
    // @ts-ignore: Unreachable code error
    console.log("hello");
}

It's worth noting that the official documentation advises to use this feature "very sparingly". In most cases, it's better to cast to any as it communicates intent more clearly.

Prior advice:

To disable tslint locally, you can use /* tslint:disable-next-line */. Keep in mind that disabling tslint may not necessarily solve compiler errors.

If needed, you can temporarily cast $ to any:

delete ($ as any).summernote.options.keyMap.pc.TAB

This method allows you to access the desired properties without restrictions.

Answer 2

If you're using Typescript 2.6 or later, there's a new feature that allows you to ignore a compiler error or warning for a specific line of code:

if (false) {
    // @ts-ignore: Unreachable code error
    console.log("hello");
}

It's worth noting that the official documentation advises to use this feature "very sparingly". In most cases, it's better to cast to any as it communicates intent more clearly.

Prior advice:

To disable tslint locally, you can use /* tslint:disable-next-line */. Keep in mind that disabling tslint may not necessarily solve compiler errors.

If needed, you can temporarily cast $ to any:

delete ($ as any).summernote.options.keyMap.pc.TAB

This method allows you to access the desired properties without restrictions.

Answer 3

Answer №2

`@ts-expect-error`

TypeScript 3.9 brings a fresh addition with the @ts-expect-error magic comment. This new directive aims to:

function similarly to @ts-ignore
raise an error if it turns out that no compiler error has actually been suppressed (indicating a redundant flag)

if (false) {
  // @ts-expect-error: Let's overlook a compile error like this unreachable code 
  console.log("hello"); // compiles
}

// If @ts-expect-error doesn't suppress anything at all, a warning will be issued 
let flag = true;
// ...
if (flag) {
  // @ts-expect-error
  // ^~~~~~~~~~~~~~~^ error: "Unused '@ts-expect-error' directive.(2578)"
  console.log("hello"); 
}

Playground

What is the advice from TypeScript developers?

@ts-ignore and @ts-expect-error can be likened to a powerful tool for handling compile errors. However, developers of TypeScript recommend opting for more precise and targeted solutions within the type system for most scenarios:

We introduced ts-ignore for those rare cases that can't be addressed by existing type system mechanisms [...] there should be extremely few instances of ts-ignore in your codebase. - microsoft/TypeScript#19139

[...] at the core, we believe that suppressions should not be a common practice in TypeScript. If it's a type issue, casting is an option (hence the existence of any, casting, and shorthand module declarations). If it's a syntax issue, things will likely break regardless, rendering suppressions ineffective (as they don't impact parse errors). - microsoft/TypeScript#19573

Options for tackling specific scenarios

▶ Utilize the any type

// type assertion for single expression
delete ($ as any).summernote.options.keyMap.pc.TAB;

// create a new variable assignment for multiple uses
const $$: any = $
delete $$.summernote.options.keyMap.pc.TAB;
delete $$.summernote.options.keyMap.mac.TAB;

▶ Enhance the JQueryStatic interface

// ./global.d.ts
interface JQueryStatic {
  summernote: any;
}

// ./main.ts
delete $.summernote.options.keyMap.pc.TAB; // functions as intended

In various cases, shorthand declarations or augmentations provide convenient ways to compile modules with no or extendable types. Another effective strategy involves gradually migrating to TypeScript, while retaining yet-to-be-migrated code in .js files by utilizing the allowJs and checkJs: false compiler flags.

Answer 4

`@ts-expect-error`

TypeScript 3.9 brings a fresh addition with the @ts-expect-error magic comment. This new directive aims to:

function similarly to @ts-ignore
raise an error if it turns out that no compiler error has actually been suppressed (indicating a redundant flag)

if (false) {
  // @ts-expect-error: Let's overlook a compile error like this unreachable code 
  console.log("hello"); // compiles
}

// If @ts-expect-error doesn't suppress anything at all, a warning will be issued 
let flag = true;
// ...
if (flag) {
  // @ts-expect-error
  // ^~~~~~~~~~~~~~~^ error: "Unused '@ts-expect-error' directive.(2578)"
  console.log("hello"); 
}

Playground

What is the advice from TypeScript developers?

@ts-ignore and @ts-expect-error can be likened to a powerful tool for handling compile errors. However, developers of TypeScript recommend opting for more precise and targeted solutions within the type system for most scenarios:

We introduced ts-ignore for those rare cases that can't be addressed by existing type system mechanisms [...] there should be extremely few instances of ts-ignore in your codebase. - microsoft/TypeScript#19139

[...] at the core, we believe that suppressions should not be a common practice in TypeScript. If it's a type issue, casting is an option (hence the existence of any, casting, and shorthand module declarations). If it's a syntax issue, things will likely break regardless, rendering suppressions ineffective (as they don't impact parse errors). - microsoft/TypeScript#19573

Options for tackling specific scenarios

▶ Utilize the any type

// type assertion for single expression
delete ($ as any).summernote.options.keyMap.pc.TAB;

// create a new variable assignment for multiple uses
const $$: any = $
delete $$.summernote.options.keyMap.pc.TAB;
delete $$.summernote.options.keyMap.mac.TAB;

▶ Enhance the JQueryStatic interface

// ./global.d.ts
interface JQueryStatic {
  summernote: any;
}

// ./main.ts
delete $.summernote.options.keyMap.pc.TAB; // functions as intended

In various cases, shorthand declarations or augmentations provide convenient ways to compile modules with no or extendable types. Another effective strategy involves gradually migrating to TypeScript, while retaining yet-to-be-migrated code in .js files by utilizing the allowJs and checkJs: false compiler flags.

Answer 5

Answer №3

When encountering the error, I inserted // @ts-ignore:next-line right before it. For more information, you can check out the documentation.

Answer 6

When encountering the error, I inserted // @ts-ignore:next-line right before it. For more information, you can check out the documentation.

Answer 7

Answer №4

Before proceeding, insert the code snippet below right above the line: // @ts-ignore

Answer 8

Before proceeding, insert the code snippet below right above the line: // @ts-ignore

Answer 9

Answer №5

When utilizing eslint for checking or fixing, you have the option to disable a specific line by adding the following code snippet above the line

// eslint-disable-next-line @typescript-eslint/<RELEVANT_ESLINT_RULE>

Answer 10

When utilizing eslint for checking or fixing, you have the option to disable a specific line by adding the following code snippet above the line

// eslint-disable-next-line @typescript-eslint/<RELEVANT_ESLINT_RULE>

Answer 11

Answer №6

A curious situation I came across involved the need to deactivate TS for a specific line of JSX. In this scenario, comments are usually enclosed in curly braces, such as `{/* @ts-expect-error */}. Here's an example of the issue:

// Cannot place it here either
<MyComponent
  {/* @ts-expect-error */} // <== This will produce Unused '@ts-expect-error' directive.
  someProps={withTsIssue}
  // other props continue below, so we cannot make it a one line
  // especially with particular eslint/prettier configurations
/>

To resolve this, you can do the following:

<MyComponent
  // @ts-expect-error
  someProps={withTsIssue}
  // other props continue below, so we cannot make it a one line
  // especially with particular eslint/prettier configurations
/>

Answer 12

A curious situation I came across involved the need to deactivate TS for a specific line of JSX. In this scenario, comments are usually enclosed in curly braces, such as `{/* @ts-expect-error */}. Here's an example of the issue:

// Cannot place it here either
<MyComponent
  {/* @ts-expect-error */} // <== This will produce Unused '@ts-expect-error' directive.
  someProps={withTsIssue}
  // other props continue below, so we cannot make it a one line
  // especially with particular eslint/prettier configurations
/>

To resolve this, you can do the following:

<MyComponent
  // @ts-expect-error
  someProps={withTsIssue}
  // other props continue below, so we cannot make it a one line
  // especially with particular eslint/prettier configurations
/>

Answer 13

Answer №7

To improve your tsconfig.json, simply include the following lines:

{
  "downlevelIteration": true,
  "strictNullChecks": false,
}

By doing this, you should have no issues.

Answer 14

To improve your tsconfig.json, simply include the following lines:

{
  "downlevelIteration": true,
  "strictNullChecks": false,
}

By doing this, you should have no issues.

What is the process for turning off a TypeScript rule for a single line of code?

Answer №1

Answer №2

`@ts-expect-error`

What is the advice from TypeScript developers?

Options for tackling specific scenarios

Answer №3

Answer №4

Answer №5

Answer №6

Answer №7

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