no-confusing-non-null-assertion
)Using a non-null assertion (!
) next to an assign or equals check (=
or ==
or ===
) creates code that is confusing as it looks similar to a not equals check (!=
!==
).
a! == b; // a non-null assertions(`!`) and an equals test(`==`) a !== b; // not equals test(`!==`) a! === b; // a non-null assertions(`!`) and an triple equals test(`===`)
Examples of incorrect code for this rule:
interface Foo { bar?: string; num?: number; } const foo: Foo = getFoo(); const isEqualsBar = foo.bar! == 'hello'; const isEqualsNum = 1 + foo.num! == 2;
Examples of correct code for this rule:
interface Foo { bar?: string; num?: number; } const foo: Foo = getFoo(); const isEqualsBar = foo.bar == 'hello'; const isEqualsNum = (1 + foo.num!) == 2;
If you don't care about this confusion, then you will not need this rule.