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var composeArgs = require('./_composeArgs'),
composeArgsRight = require('./_composeArgsRight'),
replaceHolders = require('./_replaceHolders');
/** Used as the internal argument placeholder. */
var PLACEHOLDER = '__lodash_placeholder__';
/** Used to compose bitmasks for function metadata. */
var WRAP_BIND_FLAG = 1,
WRAP_BIND_KEY_FLAG = 2,
WRAP_CURRY_BOUND_FLAG = 4,
WRAP_CURRY_FLAG = 8,
WRAP_ARY_FLAG = 128,
WRAP_REARG_FLAG = 256;
/* Built-in 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 used 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` modify function arguments, making the order in which they are
* executed important, preventing the merging of metadata. However, we make
* an exception for a safe combined 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 < (WRAP_BIND_FLAG | WRAP_BIND_KEY_FLAG | WRAP_ARY_FLAG);
var isCombo =
((srcBitmask == WRAP_ARY_FLAG) && (bitmask == WRAP_CURRY_FLAG)) ||
((srcBitmask == WRAP_ARY_FLAG) && (bitmask == WRAP_REARG_FLAG) && (data[7].length <= source[8])) ||
((srcBitmask == (WRAP_ARY_FLAG | WRAP_REARG_FLAG)) && (source[7].length <= source[8]) && (bitmask == WRAP_CURRY_FLAG));
// Exit early if metadata can't be merged.
if (!(isCommon || isCombo)) {
return data;
}
// Use source `thisArg` if available.
if (srcBitmask & WRAP_BIND_FLAG) {
data[2] = source[2];
// Set when currying a bound function.
newBitmask |= bitmask & WRAP_BIND_FLAG ? 0 : WRAP_CURRY_BOUND_FLAG;
}
// Compose partial arguments.
var value = source[3];
if (value) {
var partials = data[3];
data[3] = partials ? composeArgs(partials, value, source[4]) : value;
data[4] = partials ? replaceHolders(data[3], PLACEHOLDER) : source[4];
}
// Compose partial right arguments.
value = source[5];
if (value) {
partials = data[5];
data[5] = partials ? composeArgsRight(partials, value, source[6]) : value;
data[6] = partials ? replaceHolders(data[5], PLACEHOLDER) : source[6];
}
// Use source `argPos` if available.
value = source[7];
if (value) {
data[7] = value;
}
// Use source `ary` if it's smaller.
if (srcBitmask & WRAP_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;
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