Fix type narrowing for nonEmptyArray (#185)

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Eugene 2023-07-14 23:24:56 +01:00 committed by GitHub
parent 9265e9072d
commit 3177d11801
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2 changed files with 61 additions and 12 deletions

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@ -384,7 +384,7 @@ is.oddInteger = isAbsoluteMod2(1);
is.emptyArray = (value: unknown): value is never[] => is.array(value) && value.length === 0;
is.nonEmptyArray = (value: unknown): value is [unknown, ...unknown[]] => is.array(value) && value.length > 0;
is.nonEmptyArray = <T = unknown, Item = unknown>(value: T | Item[]): value is (T extends Item[] ? [Item, ...Item[]] : T) => is.array(value) && value.length > 0;
is.emptyString = (value: unknown): value is '' => is.string(value) && value.length === 0;
@ -575,7 +575,7 @@ type Assert = {
nodeStream: (value: unknown) => asserts value is NodeStream;
infinite: (value: unknown) => asserts value is number;
emptyArray: (value: unknown) => asserts value is never[];
nonEmptyArray: (value: unknown) => asserts value is [unknown, ...unknown[]];
nonEmptyArray: <T = unknown, Item = unknown>(value: T | Item[]) => asserts value is (T extends Item[] ? [Item, ...Item[]] : T);
emptyString: (value: unknown) => asserts value is '';
emptyStringOrWhitespace: (value: unknown) => asserts value is string;
nonEmptyString: (value: unknown) => asserts value is string;
@ -681,7 +681,7 @@ export const assert: Assert = {
nodeStream: (value: unknown): asserts value is NodeStream => assertType(is.nodeStream(value), AssertionTypeDescription.nodeStream, value),
infinite: (value: unknown): asserts value is number => assertType(is.infinite(value), AssertionTypeDescription.infinite, value),
emptyArray: (value: unknown): asserts value is never[] => assertType(is.emptyArray(value), AssertionTypeDescription.emptyArray, value),
nonEmptyArray: (value: unknown): asserts value is [unknown, ...unknown[]] => assertType(is.nonEmptyArray(value), AssertionTypeDescription.nonEmptyArray, value),
nonEmptyArray: <T = unknown, Item = unknown>(value: T | Item[]): asserts value is (T extends Item[] ? [Item, ...Item[]] : T) => assertType(is.nonEmptyArray(value), AssertionTypeDescription.nonEmptyArray, value),
emptyString: (value: unknown): asserts value is '' => assertType(is.emptyString(value), AssertionTypeDescription.emptyString, value),
emptyStringOrWhitespace: (value: unknown): asserts value is string => assertType(is.emptyStringOrWhitespace(value), AssertionTypeDescription.emptyStringOrWhitespace, value),
nonEmptyString: (value: unknown): asserts value is string => assertType(is.nonEmptyString(value), AssertionTypeDescription.nonEmptyString, value),

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@ -1448,16 +1448,65 @@ test('is.nonEmptyArray', t => {
assert.nonEmptyArray(new Array()); // eslint-disable-line @typescript-eslint/no-array-constructor
});
// https://github.com/sindresorhus/is/issues/174
// {
// const strings = ['foo', 'bar']
// const function_ = (value: string) => value;
{
const strings = ['🦄', 'unicorn'];
const function_ = (value: string) => value;
// if (is.nonEmptyArray(strings)) {
// const value = strings[0]
// function_(value);
// }
// }
if (is.nonEmptyArray(strings)) {
const value = strings[0];
function_(value);
}
}
{
const mixed = ['🦄', 'unicorn', 1, 2];
const function_ = (value: string | number) => value;
if (is.nonEmptyArray(mixed)) {
const value = mixed[0];
function_(value);
}
}
{
const arrays = [['🦄'], ['unicorn']];
const function_ = (value: string[]) => value;
if (is.nonEmptyArray(arrays)) {
const value = arrays[0];
function_(value);
}
}
{
const strings = ['🦄', 'unicorn'];
const function_ = (value: string) => value;
assert.nonEmptyArray(strings);
const value = strings[0];
function_(value);
}
{
const mixed = ['🦄', 'unicorn', 1, 2];
const function_ = (value: string | number) => value;
assert.nonEmptyArray(mixed);
const value = mixed[0];
function_(value);
}
{
const arrays = [['🦄'], ['unicorn']];
const function_ = (value: string[]) => value;
assert.nonEmptyArray(arrays);
const value = arrays[0];
function_(value);
}
});
test('is.emptyString', t => {