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math.js ES6 example
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import { format, isNumber, sign } from 'number'; | |
import { isString } from 'string'; | |
/** | |
* @constructor Range | |
* Create a range. A range has a start, step, and end, and contains functions | |
* to iterate over the range. | |
* | |
* A range can be constructed as: | |
* var range = new Range(start, end); | |
* var range = new Range(start, end, step); | |
* | |
* To get the result of the range: | |
* range.forEach(function (x) { | |
* console.log(x); | |
* }); | |
* range.map(function (x) { | |
* return math.sin(x); | |
* }); | |
* range.toArray(); | |
* | |
* Example usage: | |
* var c = new Range(2, 6); // 2:1:5 | |
* c.toArray(); // [2, 3, 4, 5] | |
* var d = new Range(2, -3, -1); // 2:-1:-2 | |
* d.toArray(); // [2, 1, 0, -1, -2] | |
* | |
* @param {Number} start included lower bound | |
* @param {Number} end excluded upper bound | |
* @param {Number} [step] step size, default value is 1 | |
*/ | |
export default function Range(start, end, step) { | |
if (!(this instanceof Range)) { | |
throw new SyntaxError('Constructor must be called with the new operator'); | |
} | |
if (start != null && !isNumber(start)) { | |
throw new TypeError('Parameter start must be a number'); | |
} | |
if (end != null && !isNumber(end)) { | |
throw new TypeError('Parameter end must be a number'); | |
} | |
if (step != null && !isNumber(step)) { | |
throw new TypeError('Parameter step must be a number'); | |
} | |
this.start = (start != null) ? parseFloat(start) : 0; | |
this.end = (end != null) ? parseFloat(end) : 0; | |
this.step = (step != null) ? parseFloat(step) : 1; | |
} | |
/** | |
* Parse a string into a range, | |
* The string contains the start, optional step, and end, separated by a colon. | |
* If the string does not contain a valid range, null is returned. | |
* For example str='0:2:11'. | |
* @param {String} str | |
* @return {Range | null} range | |
*/ | |
Range.parse = function (str) { | |
if (!isString(str)) { | |
return null; | |
} | |
var args = str.split(':'); | |
var nums = args.map(function (arg) { | |
return parseFloat(arg); | |
}); | |
var invalid = nums.some(function (num) { | |
return isNaN(num); | |
}); | |
if(invalid) { | |
return null; | |
} | |
switch (nums.length) { | |
case 2: return new Range(nums[0], nums[1]); | |
case 3: return new Range(nums[0], nums[2], nums[1]); | |
default: return null; | |
} | |
}; | |
/** | |
* Create a clone of the range | |
* @return {Range} clone | |
*/ | |
Range.prototype.clone = function () { | |
return new Range(this.start, this.end, this.step); | |
}; | |
/** | |
* Test whether an object is a Range | |
* @param {*} object | |
* @return {Boolean} isRange | |
*/ | |
Range.isRange = function (object) { | |
return (object instanceof Range); | |
}; | |
/** | |
* Retrieve the size of the range. | |
* Returns an array containing one number, the number of elements in the range. | |
* @returns {Number[]} size | |
*/ | |
Range.prototype.size = function () { | |
var len = 0, | |
start = this.start, | |
step = this.step, | |
end = this.end, | |
diff = end - start; | |
if (sign(step) == sign(diff)) { | |
len = Math.ceil((diff) / step); | |
} | |
else if (diff == 0) { | |
len = 0; | |
} | |
if (isNaN(len)) { | |
len = 0; | |
} | |
return [len]; | |
}; | |
/** | |
* Calculate the minimum value in the range | |
* @return {Number | undefined} min | |
*/ | |
Range.prototype.min = function () { | |
var size = this.size()[0]; | |
if (size > 0) { | |
if (this.step > 0) { | |
// positive step | |
return this.start; | |
} | |
else { | |
// negative step | |
return this.start + (size - 1) * this.step; | |
} | |
} | |
else { | |
return undefined; | |
} | |
}; | |
/** | |
* Calculate the maximum value in the range | |
* @return {Number | undefined} max | |
*/ | |
Range.prototype.max = function () { | |
var size = this.size()[0]; | |
if (size > 0) { | |
if (this.step > 0) { | |
// positive step | |
return this.start + (size - 1) * this.step; | |
} | |
else { | |
// negative step | |
return this.start; | |
} | |
} | |
else { | |
return undefined; | |
} | |
}; | |
/** | |
* Execute a callback function for each value in the range. | |
* @param {function} callback The callback method is invoked with three | |
* parameters: the value of the element, the index | |
* of the element, and the Matrix being traversed. | |
*/ | |
Range.prototype.forEach = function (callback) { | |
var x = this.start; | |
var step = this.step; | |
var end = this.end; | |
var i = 0; | |
if (step > 0) { | |
while (x < end) { | |
callback(x, i, this); | |
x += step; | |
i++; | |
} | |
} | |
else if (step < 0) { | |
while (x > end) { | |
callback(x, i, this); | |
x += step; | |
i++; | |
} | |
} | |
}; | |
/** | |
* Execute a callback function for each value in the Range, and return the | |
* results as an array | |
* @param {function} callback The callback method is invoked with three | |
* parameters: the value of the element, the index | |
* of the element, and the Matrix being traversed. | |
* @returns {Array} array | |
*/ | |
Range.prototype.map = function (callback) { | |
var array = []; | |
this.forEach(function (value, index, obj) { | |
array[index] = callback(value, index, obj); | |
}); | |
return array; | |
}; | |
/** | |
* Create an Array with a copy of the Ranges data | |
* @returns {Array} array | |
*/ | |
Range.prototype.toArray = function () { | |
var array = []; | |
this.forEach(function (value, index) { | |
array[index] = value; | |
}); | |
return array; | |
}; | |
/** | |
* Get the primitive value of the Range, a one dimensional array | |
* @returns {Array} array | |
*/ | |
Range.prototype.valueOf = function () { | |
// TODO: implement a caching mechanism for range.valueOf() | |
return this.toArray(); | |
}; | |
/** | |
* Get a string representation of the range, with optional formatting options. | |
* Output is formatted as 'start:step:end', for example '2:6' or '0:0.2:11' | |
* @param {Object | Number | Function} [options] Formatting options. See | |
* lib/util/number:format for a | |
* description of the available | |
* options. | |
* @returns {String} str | |
*/ | |
Range.prototype.format = function (options) { | |
var str = format(this.start, options); | |
if (this.step != 1) { | |
str += ':' + format(this.step, options); | |
} | |
str += ':' + format(this.end, options); | |
return str; | |
}; | |
/** | |
* Get a string representation of the range. | |
* @returns {String} | |
*/ | |
Range.prototype.toString = function () { | |
return this.format(); | |
}; | |
/** | |
* Get a JSON representation of the range | |
* @returns {Object} Returns a JSON object structured as: | |
* `{"mathjs": "Range", "start": 2, "end": 4, "step": 1}` | |
*/ | |
Range.prototype.toJSON = function () { | |
return { | |
mathjs: 'Range', | |
start: this.start, | |
end: this.end, | |
step: this.step | |
}; | |
}; | |
/** | |
* Instantiate a Range from a JSON object | |
* @param {Object} json A JSON object structured as: | |
* `{"mathjs": "Range", "start": 2, "end": 4, "step": 1}` | |
* @return {Range} | |
*/ | |
Range.fromJSON = function (json) { | |
return new Range(json.start, json.end, json.step); | |
}; |
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// no need for 'use strict' pragma (ES6 modules are always strict) | |
// and no need to export a factory function, as ES6 modules | |
// can be as cyclical as you like | |
import { Complex, Range, Index, Matrix, Unit, Help, ResultSet, BigNumber }; | |
// Using objects like `math.type` makes tree-shaking impossible and | |
// minification less effective. If you were okay with a single-level API... | |
// | |
// import { Range } from 'math' | |
// | |
// ...rather than... | |
// | |
// const Range = require('math').type.Range; | |
// | |
// ...then you could avoid that. But since `reviver` needs to access | |
// constructors by name, you'd need to recreate `math.type` for | |
// anyone that imported this module | |
const type = { | |
Complex, | |
Range, | |
Index, | |
Matrix, | |
Unit, | |
Help, | |
ResultSet, | |
BigNumber | |
}; | |
/** | |
* Instantiate mathjs data types from their JSON representation | |
* @param {string} key | |
* @param {*} value | |
* @returns {*} Returns the revived object | |
*/ | |
export default function reviver(key, value) { | |
var name = value && value.mathjs; | |
var constructor = type[name]; | |
if (constructor && constructor.fromJSON) { | |
return constructor.fromJSON(value); | |
} | |
return value; | |
} |
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