Merge pull request #77 from TehShrike/v2

deepmerge 2: merge harder

changelog.md

@@ -1,3 +1,11 @@
+# [2.0.0](https://github.com/KyleAMathews/deepmerge/releases/tag/v2.0.0)
+
+- breaking: the array merge algorithm has changed from a complicated thing to `target.concat(source).map(element => cloneUnlessOtherwiseSpecified(element, optionsArgument))`
+- breaking: The `clone` option now defaults to `true`
+- feature: `merge.all` now accepts an array of any size, even 0 or 1 elements
+
+See [pull request 77](https://github.com/KyleAMathews/deepmerge/pull/77).
+
 # [1.5.2](https://github.com/KyleAMathews/deepmerge/releases/tag/v1.5.2)
 
 - fix: no longer attempts to merge React elements [#76](https://github.com/KyleAMathews/deepmerge/issues/76)

index.js

@@ -1,70 +1,64 @@
 var isMergeableObject = require('is-mergeable-object')
 
 function emptyTarget(val) {
-    return Array.isArray(val) ? [] : {}
+	return Array.isArray(val) ? [] : {}
 }
 
-function cloneIfNecessary(value, optionsArgument) {
-    var clone = optionsArgument && optionsArgument.clone === true
-    return (clone && isMergeableObject(value)) ? deepmerge(emptyTarget(value), value, optionsArgument) : value
+function cloneUnlessOtherwiseSpecified(value, optionsArgument) {
+	var clone = !optionsArgument || optionsArgument.clone !== false
+
+	return (clone && isMergeableObject(value))
+		? deepmerge(emptyTarget(value), value, optionsArgument)
+		: value
 }
 
 function defaultArrayMerge(target, source, optionsArgument) {
-    var destination = target.slice()
-    source.forEach(function(e, i) {
-        if (typeof destination[i] === 'undefined') {
-            destination[i] = cloneIfNecessary(e, optionsArgument)
-        } else if (isMergeableObject(e)) {
-            destination[i] = deepmerge(target[i], e, optionsArgument)
-        } else if (target.indexOf(e) === -1) {
-            destination.push(cloneIfNecessary(e, optionsArgument))
-        }
-    })
-    return destination
+	return target.concat(source).map(function(element) {
+		return cloneUnlessOtherwiseSpecified(element, optionsArgument)
+	})
 }
 
 function mergeObject(target, source, optionsArgument) {
-    var destination = {}
-    if (isMergeableObject(target)) {
-        Object.keys(target).forEach(function(key) {
-            destination[key] = cloneIfNecessary(target[key], optionsArgument)
-        })
-    }
-    Object.keys(source).forEach(function(key) {
-        if (!isMergeableObject(source[key]) || !target[key]) {
-            destination[key] = cloneIfNecessary(source[key], optionsArgument)
-        } else {
-            destination[key] = deepmerge(target[key], source[key], optionsArgument)
-        }
-    })
-    return destination
+	var destination = {}
+	if (isMergeableObject(target)) {
+		Object.keys(target).forEach(function(key) {
+			destination[key] = cloneUnlessOtherwiseSpecified(target[key], optionsArgument)
+		})
+	}
+	Object.keys(source).forEach(function(key) {
+		if (!isMergeableObject(source[key]) || !target[key]) {
+			destination[key] = cloneUnlessOtherwiseSpecified(source[key], optionsArgument)
+		} else {
+			destination[key] = deepmerge(target[key], source[key], optionsArgument)
+		}
+	})
+	return destination
 }
 
 function deepmerge(target, source, optionsArgument) {
-    var sourceIsArray = Array.isArray(source)
-    var targetIsArray = Array.isArray(target)
-    var options = optionsArgument || { arrayMerge: defaultArrayMerge }
-    var sourceAndTargetTypesMatch = sourceIsArray === targetIsArray
+	var sourceIsArray = Array.isArray(source)
+	var targetIsArray = Array.isArray(target)
+	var options = optionsArgument || { arrayMerge: defaultArrayMerge }
+	var sourceAndTargetTypesMatch = sourceIsArray === targetIsArray
 
-    if (!sourceAndTargetTypesMatch) {
-        return cloneIfNecessary(source, optionsArgument)
-    } else if (sourceIsArray) {
-        var arrayMerge = options.arrayMerge || defaultArrayMerge
-        return arrayMerge(target, source, optionsArgument)
-    } else {
-        return mergeObject(target, source, optionsArgument)
-    }
+	if (!sourceAndTargetTypesMatch) {
+		return cloneUnlessOtherwiseSpecified(source, optionsArgument)
+	} else if (sourceIsArray) {
+		var arrayMerge = options.arrayMerge || defaultArrayMerge
+		return arrayMerge(target, source, optionsArgument)
+	} else {
+		return mergeObject(target, source, optionsArgument)
+	}
 }
 
 deepmerge.all = function deepmergeAll(array, optionsArgument) {
-    if (!Array.isArray(array) || array.length < 2) {
-        throw new Error('first argument should be an array with at least two elements')
-    }
+	if (!Array.isArray(array)) {
+		throw new Error('first argument should be an array')
+	}
 
-    // we are sure there are at least 2 values, so it is safe to have no initial value
-    return array.reduce(function(prev, next) {
-        return deepmerge(prev, next, optionsArgument)
-    })
+	return array.reduce(function(prev, next) {
+		return deepmerge(prev, next, optionsArgument)
+	}, {})
 }
 
 module.exports = deepmerge

package.json

@@ -18,13 +18,12 @@
   },
   "main": "dist/umd.js",
   "module": "dist/es.js",
-  "browser": "dist/cjs.js",
   "engines": {
     "node": ">=0.10.0"
   },
   "scripts": {
     "build": "rollup -c",
-    "test": "npm run build && tap test/*.js && jsmd README.markdown"
+    "test": "npm run build && tap test/*.js && jsmd readme.md"
   },
   "devDependencies": {
     "is-mergeable-object": "1.1.0",