/
min_by.ts
115 lines (111 loc) · 3.03 KB
/
min_by.ts
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
// This module is browser compatible.
/**
* Returns the first element that is the smallest value of the given function or
* undefined if there are no elements
*
* @example
* ```ts
* import { minBy } from "https://deno.land/std@$STD_VERSION/collections/min_by.ts";
* import { assertEquals } from "https://deno.land/std@$STD_VERSION/assert/assert_equals.ts";
*
* const people = [
* { name: "Anna", age: 34 },
* { name: "Kim", age: 42 },
* { name: "John", age: 23 },
* ];
*
* const personWithMinAge = minBy(people, (i) => i.age);
*
* assertEquals(personWithMinAge, { name: "John", age: 23 });
* ```
*/
export function minBy<T>(
array: Iterable<T>,
selector: (el: T) => number,
): T | undefined;
/**
* Returns the first element that is the smallest value of the given function or
* undefined if there are no elements
*
* @example
* ```ts
* import { minBy } from "https://deno.land/std@$STD_VERSION/collections/min_by.ts";
*
* const people = [
* { name: "Anna" },
* { name: "Kim" },
* { name: "John" },
* ];
*
* const personWithMinName = minBy(people, (i) => i.name);
* ```
*/
export function minBy<T>(
array: Iterable<T>,
selector: (el: T) => string,
): T | undefined;
/**
* Returns the first element that is the smallest value of the given function or
* undefined if there are no elements
*
* @example
* ```ts
* import { minBy } from "https://deno.land/std@$STD_VERSION/collections/min_by.ts";
* import { assertEquals } from "https://deno.land/std@$STD_VERSION/assert/assert_equals.ts";
*
* const people = [
* { name: "Anna", age: 34n },
* { name: "Kim", age: 42n },
* { name: "John", age: 23n },
* ];
*
* const personWithMinAge = minBy(people, (i) => i.age);
*
* assertEquals(personWithMinAge, { name: "John", age: 23n });
* ```
*/
export function minBy<T>(
array: Iterable<T>,
selector: (el: T) => bigint,
): T | undefined;
/**
* Returns the first element that is the smallest value of the given function or
* undefined if there are no elements
*
* @example
* ```ts
* import { minBy } from "https://deno.land/std@$STD_VERSION/collections/min_by.ts";
*
* const people = [
* { name: "Anna", startedAt: new Date("2020-01-01") },
* { name: "Kim", startedAt: new Date("2020-03-01") },
* { name: "John", startedAt: new Date("2019-01-01") },
* ];
*
* const personWithMinStartedAt = minBy(people, (i) => i.startedAt);
* ```
*/
export function minBy<T>(
array: Iterable<T>,
selector: (el: T) => Date,
): T | undefined;
export function minBy<T>(
array: Iterable<T>,
selector:
| ((el: T) => number)
| ((el: T) => string)
| ((el: T) => bigint)
| ((el: T) => Date),
): T | undefined {
let min: T | undefined = undefined;
let minValue: ReturnType<typeof selector> | undefined = undefined;
for (const current of array) {
const currentValue = selector(current);
if (minValue === undefined || currentValue < minValue) {
min = current;
minValue = currentValue;
}
}
return min;
}