bc518174
 王天杨
提交两个项目文件
|
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
|
const identity = (i) => i;
export const PLACE_HOLDER = {
'@@functional/placeholder': true,
};
const isPlaceHolder = (val) => val === PLACE_HOLDER;
const curry0 = (fn) => function _curried(...args) {
if (args.length === 0 || args.length === 1 && isPlaceHolder(args[0])) {
return _curried;
}
return fn(...args);
};
const curryN = (n, fn) => {
if (n === 1) {
return fn;
}
return curry0((...args) => {
const argsLength = args.filter((arg) => arg !== PLACE_HOLDER).length;
if (argsLength >= n) {
return fn(...args);
}
return curryN(n - argsLength, curry0((...restArgs) => {
const newArgs = args.map((arg) => (isPlaceHolder(arg) ? restArgs.shift() : arg));
return fn(...newArgs, ...restArgs);
}));
});
};
export const curry = (fn) => curryN(fn.length, fn);
export const range = (begin, end) => {
const arr = [];
for (let i = begin; i < end; ++i) {
arr[i - begin] = i;
}
return arr;
};
export const map = curry((fn, arr) => {
if (Array.isArray(arr)) {
return arr.map(fn);
}
return Object.keys(arr).map((key) => arr[key]).map(fn);
});
export const compose = (...args) => {
if (!args.length) {
return identity;
}
const fns = args.reverse();
// first function can receive multiply arguments
const firstFn = fns[0];
const tailsFn = fns.slice(1);
return (...composeArgs) => tailsFn.reduce((res, fn) => fn(res),
firstFn(...composeArgs));
};
export const reverse = (arr) => {
if (Array.isArray(arr)) {
return arr.reverse();
}
// can be string
return arr.split('').reverse.join('');
};
export const memoize = (fn) => {
let lastArgs = null;
let lastResult = null;
return (...args) => {
if (lastArgs && args.every((val, i) => val === lastArgs[i])) {
return lastResult;
}
lastArgs = args;
lastResult = fn(...args);
return lastResult;
};
};
|
