mathjs
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Math.js is an extensive math library for JavaScript and Node.js. It features a flexible expression parser with support for symbolic computation, comes with a large set of built-in functions and constants, and offers an integrated solution to work with dif
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JavaScript
const stringify = require('../../utils/string').stringify
const escape = require('../../utils/string').escape
const isSafeProperty = require('../../utils/customs').isSafeProperty
const hasOwnProperty = require('../../utils/object').hasOwnProperty
function factory (type, config, load, typed) {
const Node = load(require('./Node'))
/**
* @constructor ObjectNode
* @extends {Node}
* Holds an object with keys/values
* @param {Object.<string, Node>} [properties] object with key/value pairs
*/
function ObjectNode (properties) {
if (!(this instanceof ObjectNode)) {
throw new SyntaxError('Constructor must be called with the new operator')
}
this.properties = properties || {}
// validate input
if (properties) {
if (!(typeof properties === 'object') || !Object.keys(properties).every(function (key) {
return type.isNode(properties[key])
})) {
throw new TypeError('Object containing Nodes expected')
}
}
}
ObjectNode.prototype = new Node()
ObjectNode.prototype.type = 'ObjectNode'
ObjectNode.prototype.isObjectNode = true
/**
* Compile a node into a JavaScript function.
* This basically pre-calculates as much as possible and only leaves open
* calculations which depend on a dynamic scope with variables.
* @param {Object} math Math.js namespace with functions and constants.
* @param {Object} argNames An object with argument names as key and `true`
* as value. Used in the SymbolNode to optimize
* for arguments from user assigned functions
* (see FunctionAssignmentNode) or special symbols
* like `end` (see IndexNode).
* @return {function} Returns a function which can be called like:
* evalNode(scope: Object, args: Object, context: *)
*/
ObjectNode.prototype._compile = function (math, argNames) {
const evalEntries = {}
for (const key in this.properties) {
if (hasOwnProperty(this.properties, key)) {
// we stringify/parse the key here to resolve unicode characters,
// so you cannot create a key like {"co\\u006Estructor": null}
const stringifiedKey = stringify(key)
const parsedKey = JSON.parse(stringifiedKey)
if (!isSafeProperty(this.properties, parsedKey)) {
throw new Error('No access to property "' + parsedKey + '"')
}
evalEntries[parsedKey] = this.properties[key]._compile(math, argNames)
}
}
return function evalObjectNode (scope, args, context) {
const obj = {}
for (const key in evalEntries) {
if (hasOwnProperty(evalEntries, key)) {
obj[key] = evalEntries[key](scope, args, context)
}
}
return obj
}
}
/**
* Execute a callback for each of the child nodes of this node
* @param {function(child: Node, path: string, parent: Node)} callback
*/
ObjectNode.prototype.forEach = function (callback) {
for (const key in this.properties) {
if (this.properties.hasOwnProperty(key)) {
callback(this.properties[key], 'properties[' + stringify(key) + ']', this)
}
}
}
/**
* Create a new ObjectNode having it's childs be the results of calling
* the provided callback function for each of the childs of the original node.
* @param {function(child: Node, path: string, parent: Node): Node} callback
* @returns {ObjectNode} Returns a transformed copy of the node
*/
ObjectNode.prototype.map = function (callback) {
const properties = {}
for (const key in this.properties) {
if (this.properties.hasOwnProperty(key)) {
properties[key] = this._ifNode(callback(this.properties[key],
'properties[' + stringify(key) + ']', this))
}
}
return new ObjectNode(properties)
}
/**
* Create a clone of this node, a shallow copy
* @return {ObjectNode}
*/
ObjectNode.prototype.clone = function () {
const properties = {}
for (const key in this.properties) {
if (this.properties.hasOwnProperty(key)) {
properties[key] = this.properties[key]
}
}
return new ObjectNode(properties)
}
/**
* Get string representation
* @param {Object} options
* @return {string} str
* @override
*/
ObjectNode.prototype._toString = function (options) {
const entries = []
for (const key in this.properties) {
if (this.properties.hasOwnProperty(key)) {
entries.push(stringify(key) + ': ' + this.properties[key].toString(options))
}
}
return '{' + entries.join(', ') + '}'
}
/**
* Get a JSON representation of the node
* @returns {Object}
*/
ObjectNode.prototype.toJSON = function () {
return {
mathjs: 'ObjectNode',
properties: this.properties
}
}
/**
* Instantiate an OperatorNode from its JSON representation
* @param {Object} json An object structured like
* `{"mathjs": "ObjectNode", "properties": {...}}`,
* where mathjs is optional
* @returns {ObjectNode}
*/
ObjectNode.fromJSON = function (json) {
return new ObjectNode(json.properties)
}
/**
* Get HTML representation
* @param {Object} options
* @return {string} str
* @override
*/
ObjectNode.prototype.toHTML = function (options) {
const entries = []
for (const key in this.properties) {
if (this.properties.hasOwnProperty(key)) {
entries.push('<span class="math-symbol math-property">' + escape(key) + '</span>' + '<span class="math-operator math-assignment-operator math-property-assignment-operator math-binary-operator">:</span>' + this.properties[key].toHTML(options))
}
}
return '<span class="math-parenthesis math-curly-parenthesis">{</span>' + entries.join('<span class="math-separator">,</span>') + '<span class="math-parenthesis math-curly-parenthesis">}</span>'
}
/**
* Get LaTeX representation
* @param {Object} options
* @return {string} str
*/
ObjectNode.prototype._toTex = function (options) {
const entries = []
for (const key in this.properties) {
if (this.properties.hasOwnProperty(key)) {
entries.push('\\mathbf{' + key + ':} & ' + this.properties[key].toTex(options) + '\\\\')
}
}
return `\\left\\{\\begin{array}{ll}${entries.join('\n')}\\end{array}\\right\\}`
}
return ObjectNode
}
exports.name = 'ObjectNode'
exports.path = 'expression.node'
exports.factory = factory