90 lines
3.0 KiB
JavaScript
90 lines
3.0 KiB
JavaScript
|
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;
|