chance-generators - npm Package Compare versions

Comparing version 2.5.1 to 2.6.0

lib/chance-generators.js

@@ -24,2 +24,14 @@ /*global define*/
 
+  function getMin(value) {
+    if (typeof value === 'number') {
+      return value
+    }
+
+    if (value && value.isGenerator && value.args[0] && value.args[0].min) {
+      return value.args[0].min
+    }
+
+    return 0
+  }
+
   function unwrap (v) {
@@ -153,2 +165,21 @@ if (Array.isArray(v)) {
         return uniqueGenerator
+      },
+      weighted: function (data, weights) {
+        var generator = generatorFunction('weighted', [data, weights], function () {
+          generator.lastValue = chance.weighted(data, weights)
+          generator.lastUnwrappedValue = unwrap(generator.lastValue)
+          return generator.lastUnwrappedValue
+        })
+
+        installMapFunction(generator)
+
+        generator.shrink = function (data) {
+          return shrinkers.weighted(generator, data)
+        }
+
+        generator.expand = function (data) {
+          return expanders.weighted(generator, data)
+        }
+
+        return generator
       }
@@ -192,10 +223,4 @@ }
 
-        var minLength = 0
+        var minLength = getMin(length)
 
-        if (typeof length === 'number') {
-          minLength = length
-        } else if (length && length.isGenerator && length.args[0] && length.args[0].min) {
-          minLength = length.args[0].min
-        }
-
         var dataGenerator = generator.args[0]
@@ -258,16 +283,4 @@ if (dataGenerator.shrink) {
         var count = generator.args[1]
-        if (count && count.shrink) {
-          count = count.shrink(data.length)
-        } else {
-          count = data.length
-        }
+        var minCount = getMin(count)
 
-        var minCount = 0
-
-        if (typeof count === 'number') {
-          minCount = count
-        } else if (count && count.isGenerator && count.args[0] && count.args[0].min) {
-          minCount = count.args[0].min
-        }
-
         return that.arraySplicer(data, { min: minCount })
@@ -298,3 +311,2 @@ },
         var options = generator.args[0] || {}
-        var length = options.length
 
@@ -305,14 +317,15 @@ if (data.length === 0) {
 
-        var minLength = 0
+        var length = options.length
+        var minLength = getMin(length)
 
-        if (typeof length === 'number') {
-          minLength = length
-        } else if (length && length.min) {
-          minLength = options.length.min
-        } else if (length && length.isGenerator && length.args[0] && length.args[0].min) {
-          minLength = length.args[0].min
-        }
-
         return that.stringSplicer(data, { min: minLength })
       },
+      weighted: function (generator, data) {
+        var shrinkable = generator.lastUnwrappedValue === data && generator.lastValue.shrink
+        if (shrinkable) {
+          return generator.lastValue.shrink(data)
+        } else {
+          return that.constant(data)
+        }
+      },
       integer: minMaxShrinker,
@@ -400,2 +413,10 @@ natural: minMaxShrinker,
         return that.shape(newShape)
+      },
+      weighted: function (generator, data) {
+        var expandable = generator.lastUnwrappedValue === data && generator.lastValue.expand
+        if (expandable) {
+          return generator.lastValue.expand(data)
+        } else {
+          return that.constant(data)
+        }
       }
@@ -402,0 +423,0 @@ }

package.json

 {
   "name": "chance-generators",
-  "version": "2.5.1",
+  "version": "2.6.0",
   "description": "Random generators based on changejs",
@@ -5,0 +5,0 @@ "main": "lib/chance-generators.js",

test/chance-generators.spec.js

@@ -654,2 +654,78 @@ /*global describe, it*/
 
+  describe('weighted', () => {
+    describe('given an array of values and weights', () => {
+      it('generates values picks values from the array based on the weights', () => {
+        const arr = [42, chance.string, 666, chance.character]
+        const weights = [10, 20, 1, 20]
+        const generator = chance.weighted(arr, weights)
+        expect([generator(), generator(), generator(), generator()], 'to satisfy', [
+          '(n25SSlGlheH#ySk0', 'b', 42, '1'
+        ])
+      })
+    })
+
+    describe('shrink', () => {
+      describe('when the picked value is a generator', () => {
+        it('shrinks the value with regards to the picked generator', () => {
+          const arr = [chance.string, chance.natural({ min: 10, max: 20 })]
+          const weights = [10, 20]
+          const generator = chance.weighted(arr, weights)
+
+          const value = generator()
+          const shrunkenGenerator = generator.shrink(value)
+          expect([value, shrunkenGenerator(), shrunkenGenerator(), shrunkenGenerator()], 'to satisfy', [
+            18, 18, 11, 16
+          ])
+        })
+      })
+
+      describe('when the picked value is not a generator', () => {
+        it('does not shrink the value', () => {
+          const arr = [0, 1]
+          const weights = [10, 20]
+          const generator = chance.weighted(arr, weights)
+
+          const value = generator()
+          const shrunkenGenerator = generator.shrink(value)
+          expect([value, shrunkenGenerator(), shrunkenGenerator(), shrunkenGenerator()], 'to satisfy', [
+            1, 1, 1, 1
+          ])
+        })
+      })
+    })
+
+    describe('expand', () => {
+      describe('when the picked value is a generator', () => {
+        it('expands the value with regards to the picked generator', () => {
+          const arr = [chance.natural({ min: 10, max: 20 }), chance.string]
+          const weights = [10, 20]
+          const generator = chance.weighted(arr, weights)
+
+          const value = generator()
+          const expandedGenerator = generator.expand(value)
+          expect([value, expandedGenerator(), expandedGenerator(), expandedGenerator()], 'to satisfy', [
+            '(n25SSlGlheH#ySk0',
+            '(n25SSlGnheH#ySk0',
+            '(n25SSlGlheH#ySk0',
+            '(n25SSlGlheH#ySkF'
+          ])
+        })
+      })
+
+      describe('when the picked value is not a generator', () => {
+        it('does not expand the value', () => {
+          const arr = [0, 1]
+          const weights = [10, 20]
+          const generator = chance.weighted(arr, weights)
+
+          const value = generator()
+          const expandedGenerator = generator.expand(value)
+          expect([value, expandedGenerator(), expandedGenerator(), expandedGenerator()], 'to satisfy', [
+            1, 1, 1, 1
+          ])
+        })
+      })
+    })
+  })
+
   describe('constant', () => {
@@ -656,0 +732,0 @@ it('generate the given value', () => {

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Improved metrics

Total package byte prevSize

62969

increased by5.71%

Lines of code

1420

increased by6.37%

No dependency changes