Util

F2.Util

Methods

upperFirst([string=''])

Converts the first character of string to upper case.

Arguments

  • [string=''] (string): The string to convert.

Returns

(string): Returns the converted string.

Example

F2.Util.upperFirst('fred');
// => 'Fred'
 
F2.Util.upperFirst('FRED');
// => 'FRED

lowerFirst([string=''])

Converts the first character of string to lower case.

Arguments

  • [string=''] (string): The string to convert.

Returns

(string): Returns the converted string.

Example

F2.Util.lowerFirst('Fred');
// => 'fred'
 
F2.Util.lowerFirst('FRED');
// => 'fRED'

isString(value)

Checks if value is classified as a String primitive or object.

Arguments

  • value (*): The value to check.

Returns

(boolean): Returns true if value is a string, else false.

Example

F2.Util.isString('abc');
// => true
 
F2.Util.isString(1);
// => false

isNumber(value)

Checks if value is classified as a Number primitive or object.

Arguments

  • value (*): The value to check.

Returns

(boolean): Returns true if value is a number, else false.

Example

F2.Util.isNumber(3);
// => true

F2.Util.isNumber(Infinity);
// => true
 
F2.Util.isNumber('3');
// => false

isBoolean(value)

Checks if value is classified as a boolean primitive or object.

Arguments

  • value (*): The value to check.

Returns

(boolean): Returns true if value is a boolean, else false.

Example

F2.Util.isBoolean(false);
// => true
 
F2.Util.isBoolean(null);
// => false

isFunction(value)

Checks if value is classified as a Function object.

Arguments

  • value (*): The value to check.

Returns

(boolean): Returns true if value is a function, else false.

Example

F2.Util.isFunction(_);
// => true

isPlainObject(value)

Checks if value is a plain object, that is, an object created by the Object constructor or one with a [[Prototype]] of null.

Arguments

  • value (*): The value to check.

Returns

(boolean): Returns true if value is a plain object, else false.

Example

function Foo() {
  this.a = 1;
}
 
F2.Util.isPlainObject(new Foo);
// => false
 
F2.Util.isPlainObject([1, 2, 3]);
// => false
 
F2.Util.isPlainObject({ 'x': 0, 'y': 0 });
// => true
 
F2.Util.isPlainObject(Object.create(null));
// => true

isArray(value)

Checks if value is classified as an Array object.

Arguments

  • value (*): The value to check.

Returns

(boolean): Returns true if value is an array, else false.

Example

F2.Util.isArray([1, 2, 3]);
// => true

F2.Util.isArray('abc');
// => false

isDate(value)

Checks if value is classified as a Date object.

Arguments

  • value (*): The value to check.

Returns

(boolean): Returns true if value is a date object, else false.

Example

F2.Util.isDate(new Date);
// => true
 
F2.Util.isDate('Mon April 23 2012');
// => false

isNil(value)

Checks if value is null or undefined.

Arguments

  • value (*): The value to check.

Returns

(boolean): Returns true if value is nullish, else false.

Example

F2.Util.isNil(null);
// => true
 
F2.Util.isNil(void 0);
// => true
 
F2.Util.isNil(NaN);
// => false

isObject(value)

Checks if value is the language type of Object. (e.g. arrays, functions, objects, regexes, new Number(0), and new String(''))

Arguments

  • value (*): The value to check.

Returns

(boolean): Returns true if value is an object, else false.

Example

F2.Util.isObject({});
// => true
 
F2.Util.isObject([1, 2, 3]);
// => true
 
F2.Util.isObject(null);
// => false

mix(object, [sources])

Assigns own enumerable string keyed properties of source objects to the destination object. Source objects are applied from left to right. Subsequent sources overwrite property assignments of previous sources.

Arguments

  1. object (Object): The destination object.

  2. [sources] (...Object): The source objects. Support for up to 3 objects

Returns

(Object): Returns object.

Example

const target = {
  a: {
    value: 1
  }
};

const source = {
  a: {
    value: 2
  },
  b: 2
};

F2.Util.mix(target, source);
// => target will be { a: { value: 2 }, b2: 2 }

deepMix(object, [sources])

This method is like F2.Util.mix except that it iterates over own source properties.

Arguments

  1. object (Object): The destination object.

  2. [sources] (...Object): The source objects.

Returns

(Object): Returns object.

Example

const target = {
  a: {
    type: 'a'
  }
};

const source = {
  a: {
    value: 2
  },
  b: 2
};

F2.Util.mix(target, source);
// => target will be { a: { type: 'a', value: 2 }, b2: 2 }

indexOf(array, value)

Gets the index at which the first occurrence of value is found in array.

Arguments

  1. array (Array): The array to inspect.

  2. value (*): The value to search for.

Returns

(number): Returns the index of the matched value, else -1.

Example

F2.Util.indexOf([1, 2, 1, 2], 2);
// => 1

forEach(collection, [iteratee=_.identity])

Iterates over elements of collection and invokes iteratee for each element. The iteratee is invoked with three arguments: (value, index|key, collection). Iteratee functions may exit iteration early by explicitly returning false.

Arguments

  1. collection (Array|Object): The collection to iterate over.

  2. [iteratee=_.identity] (Function): The function invoked per iteration.

Returns

(*): Returns collection.

Example

F2.Util.each([1, 2], function(value) {
  console.log(value);
});
// => Logs `1` then `2`.
 
F2.Util.each({ 'a': 1, 'b': 2 }, function(value, key) {
  console.log(key);
});
// => Logs 'a' then 'b' (iteration order is not guaranteed).

F2.Util.each([1, 2, 3, 4, 5, 6], function(value) {
  console.log(value);
  if (value === 4) {
    return false;
  }
});
// => Logs `1`,`2`,`3`,`4`.

getPixelRatio()

Get the current pixel ratio.

Returns

(number): Returns the current pixel ratio.

getRelativePosition(point, canvas)

Convert the position of the mouse to the relative coordinate of the canvas.

Arguments

  1. point (Object): the point need to convert.

  2. canvas (Canvas): the canvas instance of chart.

Returns

(object): Returns the relative coordinate of the canvas.

Example

const mousePoint = {
  x: 10,
  y:39
};
const canvas = chart.get('canvas');
const canvasPoint = F2.Util.getRelativePosition(mousePoint, canvas);
// => { x: , y: }
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