Description
These rules are all implemented - one final case remains to be implemented: no-unsafe-argument to catch when you're passing any into an argument. (See #791 (comment))
Create a rule which uses type information to determine when you're inadvertently breaking type safety by using an any, potentially without knowing.
Often libraries (or even the typescript defs themselves) can have weak(/lazy) types which return any. If you're not careful, you can inadvertently introduce anys within your codebase, leading to bugs that aren't caught by the compiler.
Examples:
const foo = Object.create(null);
// ^^^ error: variable declaration implicitly typed as any
const bar = x.prop;
// ^^^ error: variable declaration implicitly typed as any
const baz = (1 as any);
// ^^^ error: variable declaration implicitly typed as any
const buzz = [];
// ^^^^ error: variable declaration implicitly typed as any[]
let bam: any = 1; // no error, as it's **explicitly** any
function foo(arg: string) {
// ^^^^^^^^^^^^^^^^^^^^^^^^^ error: function return type is implicitly any
if (someCondition) {
return 'str';
}
return bam;
// ^^^^^^^^^^^ error: return statement implicitly returns any
}
foo(x.prop);
// ^^^^^^ error: passed function argument implicitly typed as any
for (const fizz of bar) {}
// ^^^^^^^^^^ error: variable declaration implicitly typed as any
for (let i = foo; i < 10; i += 1) {}
// ^ error: variable declaration implicitly typed as any
// variable decls, returns, arguments, assignment expressions, ifs... Should also check assignments:
bam = foo;
// ^^^^^^^^^^ error: assignment expression implicitly uses as any
const clazz = new Clazz();
clazz.foo = foo;
// ^^^^^^^^^^^^^^^^ error: assignment expression implicitly uses as any
foo += foo;
// ^^^^^^^^^^^ error: assignment expression implicitly uses any
foo++;
// ^^^^^^ error: update expression implicitly uses anyMaybe also check things boolean things like if/while/etc?
if (foo) {}
// ^^^ error: if condition implicitly typed as any
while (foo) {}
// ^^^ error: while condition implicitly typed as any
do { } while (foo)
// ^^^ error: do...while condition implicitly typed as any
switch (foo) {
// ^^^ error: switch discriminate implicitly typed as any
case bar:
// ^^^ error: case test implicitly typed as any
break;
}Should also provide an option to go strict with property access to help with finding the source of an any via property access):
type Obj = {
foo: {
[k: string]: any;
bar: {
baz: string;
};
};
};
declare const x: Obj;
const y = x.foo.bam.baz;
// ^^^^^^^^^ error: property access implicitly returns any
// ^ error: variable declaration implicitly typed as any
const z: string = x.foo.bam.baz;
// ^^^^^^^^^ error: property access implicitly returns any
const { baz } = x.foo.bam;
// ^^^^^^^^^ error: property access implicitly returns any
// ^^^ error: destructured variable implicitly typed as any