bobiblazeski-q v1.5.0

#class: Q Documentation for additional functionality added to excellent www.ramdajs.com

Members

• class: Q
  • Q.abate(f, obj)
  • Q.amend(left, right, lKey, rKey)
  • Q.assembler(keys)
  • Q.collect(f, obj)
  • Q.curtail(fn, list)
  • Q.division(divisor, dividend)
  • Q.group(f, list)
  • Q.innerJoin(on, columns, left, right)
  • Q.isNull(f, auto, obj)
  • Q.lay(end, [start], [step])
  • Q.least(f, list)
  • Q.minus(subtrahend, minuend)
  • Q.most(f, list)
  • Q.order(f, list)
  • Q.remainder(divisor, dividend)
  • Q.sift(f, list)
  • Q.single(f, list)
  • Q.sumBy(f, list)
  • Q.taper(f, acc, obj)

##Q.abate(f, obj) Returns a new list by concatenating into list results of applying the function to all object key value pairs

Params

• f function - The function executed for each key value pair
• obj Object - The obj to consider.

Returns: Array - The list of results of applying the function to all key value pairs
Example
Q.abate(function(d){ return -d,d;},{ a:4,b:9,c:16}); //=> -4,4,-9,9,-16,16

##Q.amend(left, right, lKey, rKey) Amend left list object with keys from right list objects joining by key

Params

• left Array - The original list
• right Array - The extension list
• lKey String - The original list key
• rKey String - The extension list key, if a omitted assumed equal with lKey

Returns: function - The predicate function.
Example
var left = { id:1, b:2},{ id:2, b:2}; var right ={ id:1, d:4},{ id:2, d:5}; Q.amend(left,right,'id') => {"id":1,"b":2,"d":4},{"id":2,"b":2,"d":5}

##Q.assembler(keys) Returns a function that when supplied with arguments returns object created by given keys. Returned function sets filed where it lacks arguments to undefined, ignores surplus arguments.

Params

• keys Array - keys for the created object

Returns: * - The construct function
Example
var trend = Q.construct("year", "amount", "name"); trend(1937,100, 'foo') => { year:1937, amount: 100, name: 'foo'}

##Q.collect(f, obj) Returns a new list by collecting into list results of applying the function to all object key value pairs

Params

• f function | String - The function executed for each key value pair
• obj Object - The obj to consider.

Returns: Array - The list of results of applying the function to all key value pairs
Example
Q.collect(Math.sqrt,{ a:4,b:9,c:16}); //=> 2, 3, 4

##Q.curtail(fn, list) Returns a new list by concatenating into list results of applying the function to all elements and their index

Params

• fn function - The function executed for each key value pair
• list Array - The array

Returns: Array - The list of results of applying the function to all key value pairs
Example
Q.curtail(function(d){ return -d,d;},4,9,16); //=> -4,4,-9,9,-16,16

##Q.division(divisor, dividend) Divides two numbers. Equivalent to a / b.

Params

• divisor Number - The number you divide by
• dividend Number - The amount that you want to divide up.

Returns: Number - The quotient of dividend / divisor.
Example
Q.quotient(100,71); //=> 0.71

Q.map(Q.quotient(16),1,2,4,8,16) //=> 16,8,4,2,1

##Q.group(f, list) Splits a list into sub-lists stored in an object, based on the result of calling a String-returning function on each element, and grouping the results according to values returned.

Params

• f function | String - function or string
• list Array - The array to group

Returns: Object - An object with the output of f for keys, mapped to arrays of elements that produced that key when passed to f.
Example
Q.group(function(num) { return Math.floor(num); },4.2, 6.1, 6.4) =>( { '4': 4.2, '6': 6.1, 6.4 })

##Q.innerJoin(on, columns, left, right) Returns an inner join of two arrays.

Params

• on String | Array | function - it could be either string, array of two string or function
• columns Array | function - it could be either array of strings or function
• left Array - left array of objects to be joined
• right Array - right array of objects to be joined

Returns: * - The inner join of the arrays
Example
Q.join("id", "a","b",{id:1, a: 1},{id:2,a:3},{id:1, b: 11},{id:22,a:33}) // =>({ a: 1, b:11});

##Q.isNull(f, auto, obj) Returns the requested value or provided default value if requested value is null or undefined

Params

• f function | String - function or string
• auto Object - default value if requested value is null or undefined
• obj Object - Object containing the requested value

Returns: Object - An object with the output of f for keys, mapped to arrays of elements that produced that key when passed to f.
Example
Q.isNull({a:1},"a",2) // => 1 Q.isNull({b:1},"a",2) // => 2 Q.isNull(null,"a",3) // => 3

##Q.lay(end, start, step) Returns a list of numbers from start (inclusive) to end (exclusive) using tep.

Params

• end Number - step more than the last number in the list.
• [start] Number - first number in the list. Assumed 0 if null
• [step] Number - difference between two numbers. Assumed 1 if null

Returns: Array - The list of numbers.
Example
Q.lay(5); //=> 1, 2, 3, 4 Q.lay(53, 50); //=> 50, 51, 52 Q.lay(4, 8, -1); //=> 8, 7, 6, 5

##Q.least(f, list) Determines the smallest of a list of items as determined by pairwise comparisons from the supplied comparator

Params

• f function | String - A comparator function or field specifier for elements in the list
• list Array - A list of comparable elements

Returns: * - The smallest element in the list. undefined if the list is empty.
Example
function cmp(obj) { return obj.x; } var a = {x: 1}, b = {x: 2}, c = {x: 3}; Q.min(cmp, a, b, c); //=> {x: 1}

##Q.minus(subtrahend, minuend) Subtracts two numbers. Equivalent to a - b but curried.

Params

• subtrahend Number - The number that is to be subtracted. The second number in a subtraction.
• minuend Number - The number from which another number (the Subtrahend) is to be subtracted.

Returns: Number - The difference of minuend - subtrahend.
Example
Q.minus( 8,10); //=> 2 Q.map(Q.minus(10), 10,20,30); //=> 0,10,20

##Q.most(f, list) Determines the largest of a list of items as determined by pairwise comparisons from the supplied comparator

Params

• f function | String - A comparator function or field specifier for elements in the list
• list Array - A list of comparable elements

Returns: * - The largest element in the list. undefined if the list is empty.
Example
function cmp(obj) { return obj.x; } var a = {x: 1}, b = {x: 2}, c = {x: 3}; Q.max(cmp, a, b, c); //=> {x: 3}

##Q.order(f, list) Sorts the list according to a key generated by the supplied function.

Params

• f function | String - The function mapping list items to keys, or property string.
• list Array - The list to sort.

Returns: Array - A new list sorted by the keys generated by f.
Example
var entries = { name: 'ALICE', age: 101 }, {name: 'Bob',age: -400},{name: 'clara',age: 314.159}; Q.sort(function(d){ return Math.abs(d.age);},entries) => {"name":"ALICE","age":101},{"name":"clara","age":314.159},{"name":"Bob","age":-400} Q.sort("age", { name: 'ALICE', age: 101 }, {name: 'Bob',age: -400},{name: 'clara',age: 314.159}) => {"name":"Bob","age":-400},{"name":"ALICE","age":101},{"name":"clara","age":314.159} Q.sort("-age", { name: 'ALICE', age: 101 }, {name: 'Bob',age: -400},{name: 'clara',age: 314.159}) =>{"name":"clara","age":314.159},{"name":"ALICE","age":101},{"name":"Bob","age":-400}

##Q.remainder(divisor, dividend) Divides the second parameter by the first and returns the remainder. Note that this functions preserves the JavaScript-style behavior for modulo. For mathematical modulo see mathMod

Params

• divisor Number - The pseudo-modulus
• dividend Number - The value to the divide.

Returns: Number - The result of dividend % divisor.
Example
Q.remainder(3,17); //=> 2 // JS behavior: Q.remainder(3,-17); //=> -2 Q.remainder(17, -3); //=> 2

var isOdd = Q.modulo(2); isOdd(42); //=> 0 isOdd(21); //=> 1

##Q.sift(f, list) Returns a new list containing only those items that match a given predicate function. The predicate function is passed one argument: (value).

Params

• f function | Object - The function called per iteration, or functor description.
• list Array - The collection to iterate over.

Returns: Array - The new filtered array.
Example
var isEven = function(n) { return n % 2 === 0; }; Q.sift(isEven, 1, 2, 3, 4); //=> 2, 4

##Q.single(f, list) Returns the first element of the list which matches the predicate, or undefined if no element matches.

Params

• f function | Object - The predicate function used to determine if the element is the desired one. Or specification object
• list Array - The array to consider.

Returns: Object - The element found, or undefined.
Example
var xs = {a: 1}, {a: 2}, {a: 3}; Q.find(function(d){ return d.a == 2;}, xs); //=> {a: 2} Q.find({ a : 2}, xs); //=> {a: 2} Q.find({a: 4},(xs); //=> undefined

##Q.sumBy(f, list) Adds together all the elements of a list.

Params

• f function | String - The function retrieving value from each item, or property string.
• list Array - An array of objects

Returns: Number - The sum of all the retrieved values in the list.
Example
Q.sumBy("a",{a:2},{a:4},{a:6},{a:8},{a:100},{a:1}); //=> 121 Q.sumBy(function(d){ return 2* d.a;},{a:2},{a:4},{a:6},{a:8},{a:100},{a:1}) //=>242 Q.sumBy(Q.identity,2,4,6,8,100,100)//=> 220

##Q.taper(f, acc, obj) Returns a single item by iterating through the obj, successively calling the iterator function and passing it an accumulator value, the object value for the current key, and the current key then passing the result to the next call.

The iterator function receives two values: (acc, value)

Params

• f function - The iterator function. Receives three values, the accumulator, the object value for the current key, and the current key
• acc * - The accumulator value.
• obj Object - The object to iterate over.

Returns: * - The final, accumulated value.
Example
Q.taper(function(acc, val) { return acc+ val; }, 10, {a: 2, b : 4}); //=> 16 Q.taper(function(acc, val,key){return acc.concat( val,key);},1,"e", {a: 2, b : 4});//=>[1,"e", 2,"a",4,"b"