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