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
|
var arrayCopy = require('./arrayCopy'),
composeArgs = require('./composeArgs'),
composeArgsRight = require('./composeArgsRight'),
replaceHolders = require('./replaceHolders');
/** Used to compose bitmasks for wrapper metadata. */
var BIND_FLAG = 1,
CURRY_BOUND_FLAG = 4,
CURRY_FLAG = 8,
ARY_FLAG = 128,
REARG_FLAG = 256;
/** Used as the internal argument placeholder. */
var PLACEHOLDER = '__lodash_placeholder__';
/* Native method references for those with the same name as other `lodash` methods. */
var nativeMin = Math.min;
/**
* Merges the function metadata of `source` into `data`.
*
* Merging metadata reduces the number of wrappers required to invoke a function.
* This is possible because methods like `_.bind`, `_.curry`, and `_.partial`
* may be applied regardless of execution order. Methods like `_.ary` and `_.rearg`
* augment function arguments, making the order in which they are executed important,
* preventing the merging of metadata. However, we make an exception for a safe
* common case where curried functions have `_.ary` and or `_.rearg` applied.
*
* @private
* @param {Array} data The destination metadata.
* @param {Array} source The source metadata.
* @returns {Array} Returns `data`.
*/
function mergeData(data, source) {
var bitmask = data[1],
srcBitmask = source[1],
newBitmask = bitmask | srcBitmask,
isCommon = newBitmask < ARY_FLAG;
var isCombo =
(srcBitmask == ARY_FLAG && bitmask == CURRY_FLAG) ||
(srcBitmask == ARY_FLAG && bitmask == REARG_FLAG && data[7].length <= source[8]) ||
(srcBitmask == (ARY_FLAG | REARG_FLAG) && bitmask == CURRY_FLAG);
// Exit early if metadata can't be merged.
if (!(isCommon || isCombo)) {
return data;
}
// Use source `thisArg` if available.
if (srcBitmask & BIND_FLAG) {
data[2] = source[2];
// Set when currying a bound function.
newBitmask |= (bitmask & BIND_FLAG) ? 0 : CURRY_BOUND_FLAG;
}
// Compose partial arguments.
var value = source[3];
if (value) {
var partials = data[3];
data[3] = partials ? composeArgs(partials, value, source[4]) : arrayCopy(value);
data[4] = partials ? replaceHolders(data[3], PLACEHOLDER) : arrayCopy(source[4]);
}
// Compose partial right arguments.
value = source[5];
if (value) {
partials = data[5];
data[5] = partials ? composeArgsRight(partials, value, source[6]) : arrayCopy(value);
data[6] = partials ? replaceHolders(data[5], PLACEHOLDER) : arrayCopy(source[6]);
}
// Use source `argPos` if available.
value = source[7];
if (value) {
data[7] = arrayCopy(value);
}
// Use source `ary` if it's smaller.
if (srcBitmask & ARY_FLAG) {
data[8] = data[8] == null ? source[8] : nativeMin(data[8], source[8]);
}
// Use source `arity` if one is not provided.
if (data[9] == null) {
data[9] = source[9];
}
// Use source `func` and merge bitmasks.
data[0] = source[0];
data[1] = newBitmask;
return data;
}
module.exports = mergeData;
|
