How to disable a ts rule for a specific line?

Question

Summernote is a jQuery plugin, and I don\'t need type definitions for it. I just want to modify the object, but TS keeps throwing errors. The line bellow still gives me:

Answer 1

You can use /* tslint:disable-next-line */ to locally disable tslint. However, as this is a compiler error disabling tslint might not help.

You can always temporarily cast $ to any:

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

which will allow you to access whatever properties you want.

---

Edit: As of Typescript 2.6, you can now bypass a compiler error/warning for a specific line:

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

Note that the official docs "recommend you use [this] very sparingly". It is almost always preferable to cast to any instead as that better expresses intent.

Answer 2

@ts-expect-error

TS 3.9 introduces a new magic comment. @ts-expect-error will:

• have same functionality as @ts-ignore
• trigger an error, if actually no compiler error has been suppressed (= indicates useless flag)

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

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

---

Alternatives

@ts-ignore and @ts-expect-error can be used for all sorts of compiler errors. For type issues (like in OP), I recommend one of the following alternatives due to narrower error suppression scope:

▶ Use any type

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

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

▶ Augment JQueryStatic interface

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

// ./main.ts
delete $.summernote.options.keyMap.pc.TAB; // works

In other cases, shorthand module declarations or module augmentations for modules with no/extendable types are handy utilities. A viable strategy is also to keep not migrated code in .js and use --allowJs with checkJs: false.