mathjs/lib/expression/node/ConditionalNode.js

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.createConditionalNode = void 0;

var _is = require("../../utils/is");

var _factory = require("../../utils/factory");

var _operators = require("../operators");

var name = 'ConditionalNode';
var dependencies = ['Node'];
var createConditionalNode =
/* #__PURE__ */
(0, _factory.factory)(name, dependencies, function (_ref) {
  var Node = _ref.Node;

  /**
   * A lazy evaluating conditional operator: 'condition ? trueExpr : falseExpr'
   *
   * @param {Node} condition   Condition, must result in a boolean
   * @param {Node} trueExpr    Expression evaluated when condition is true
   * @param {Node} falseExpr   Expression evaluated when condition is true
   *
   * @constructor ConditionalNode
   * @extends {Node}
   */
  function ConditionalNode(condition, trueExpr, falseExpr) {
    if (!(this instanceof ConditionalNode)) {
      throw new SyntaxError('Constructor must be called with the new operator');
    }

    if (!(0, _is.isNode)(condition)) throw new TypeError('Parameter condition must be a Node');
    if (!(0, _is.isNode)(trueExpr)) throw new TypeError('Parameter trueExpr must be a Node');
    if (!(0, _is.isNode)(falseExpr)) throw new TypeError('Parameter falseExpr must be a Node');
    this.condition = condition;
    this.trueExpr = trueExpr;
    this.falseExpr = falseExpr;
  }

  ConditionalNode.prototype = new Node();
  ConditionalNode.prototype.type = 'ConditionalNode';
  ConditionalNode.prototype.isConditionalNode = 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: *)
   */

  ConditionalNode.prototype._compile = function (math, argNames) {
    var evalCondition = this.condition._compile(math, argNames);

    var evalTrueExpr = this.trueExpr._compile(math, argNames);

    var evalFalseExpr = this.falseExpr._compile(math, argNames);

    return function evalConditionalNode(scope, args, context) {
      return testCondition(evalCondition(scope, args, context)) ? evalTrueExpr(scope, args, context) : evalFalseExpr(scope, args, context);
    };
  };
  /**
   * Execute a callback for each of the child nodes of this node
   * @param {function(child: Node, path: string, parent: Node)} callback
   */


  ConditionalNode.prototype.forEach = function (callback) {
    callback(this.condition, 'condition', this);
    callback(this.trueExpr, 'trueExpr', this);
    callback(this.falseExpr, 'falseExpr', this);
  };
  /**
   * Create a new ConditionalNode 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 {ConditionalNode} Returns a transformed copy of the node
   */


  ConditionalNode.prototype.map = function (callback) {
    return new ConditionalNode(this._ifNode(callback(this.condition, 'condition', this)), this._ifNode(callback(this.trueExpr, 'trueExpr', this)), this._ifNode(callback(this.falseExpr, 'falseExpr', this)));
  };
  /**
   * Create a clone of this node, a shallow copy
   * @return {ConditionalNode}
   */


  ConditionalNode.prototype.clone = function () {
    return new ConditionalNode(this.condition, this.trueExpr, this.falseExpr);
  };
  /**
   * Get string representation
   * @param {Object} options
   * @return {string} str
   */


  ConditionalNode.prototype._toString = function (options) {
    var parenthesis = options && options.parenthesis ? options.parenthesis : 'keep';
    var precedence = (0, _operators.getPrecedence)(this, parenthesis); // Enclose Arguments in parentheses if they are an OperatorNode
    // or have lower or equal precedence
    // NOTE: enclosing all OperatorNodes in parentheses is a decision
    // purely based on aesthetics and readability

    var condition = this.condition.toString(options);
    var conditionPrecedence = (0, _operators.getPrecedence)(this.condition, parenthesis);

    if (parenthesis === 'all' || this.condition.type === 'OperatorNode' || conditionPrecedence !== null && conditionPrecedence <= precedence) {
      condition = '(' + condition + ')';
    }

    var trueExpr = this.trueExpr.toString(options);
    var truePrecedence = (0, _operators.getPrecedence)(this.trueExpr, parenthesis);

    if (parenthesis === 'all' || this.trueExpr.type === 'OperatorNode' || truePrecedence !== null && truePrecedence <= precedence) {
      trueExpr = '(' + trueExpr + ')';
    }

    var falseExpr = this.falseExpr.toString(options);
    var falsePrecedence = (0, _operators.getPrecedence)(this.falseExpr, parenthesis);

    if (parenthesis === 'all' || this.falseExpr.type === 'OperatorNode' || falsePrecedence !== null && falsePrecedence <= precedence) {
      falseExpr = '(' + falseExpr + ')';
    }

    return condition + ' ? ' + trueExpr + ' : ' + falseExpr;
  };
  /**
   * Get a JSON representation of the node
   * @returns {Object}
   */


  ConditionalNode.prototype.toJSON = function () {
    return {
      mathjs: 'ConditionalNode',
      condition: this.condition,
      trueExpr: this.trueExpr,
      falseExpr: this.falseExpr
    };
  };
  /**
   * Instantiate an ConditionalNode from its JSON representation
   * @param {Object} json  An object structured like
   *                       `{"mathjs": "ConditionalNode", "condition": ..., "trueExpr": ..., "falseExpr": ...}`,
   *                       where mathjs is optional
   * @returns {ConditionalNode}
   */


  ConditionalNode.fromJSON = function (json) {
    return new ConditionalNode(json.condition, json.trueExpr, json.falseExpr);
  };
  /**
   * Get HTML representation
   * @param {Object} options
   * @return {string} str
   */


  ConditionalNode.prototype.toHTML = function (options) {
    var parenthesis = options && options.parenthesis ? options.parenthesis : 'keep';
    var precedence = (0, _operators.getPrecedence)(this, parenthesis); // Enclose Arguments in parentheses if they are an OperatorNode
    // or have lower or equal precedence
    // NOTE: enclosing all OperatorNodes in parentheses is a decision
    // purely based on aesthetics and readability

    var condition = this.condition.toHTML(options);
    var conditionPrecedence = (0, _operators.getPrecedence)(this.condition, parenthesis);

    if (parenthesis === 'all' || this.condition.type === 'OperatorNode' || conditionPrecedence !== null && conditionPrecedence <= precedence) {
      condition = '<span class="math-parenthesis math-round-parenthesis">(</span>' + condition + '<span class="math-parenthesis math-round-parenthesis">)</span>';
    }

    var trueExpr = this.trueExpr.toHTML(options);
    var truePrecedence = (0, _operators.getPrecedence)(this.trueExpr, parenthesis);

    if (parenthesis === 'all' || this.trueExpr.type === 'OperatorNode' || truePrecedence !== null && truePrecedence <= precedence) {
      trueExpr = '<span class="math-parenthesis math-round-parenthesis">(</span>' + trueExpr + '<span class="math-parenthesis math-round-parenthesis">)</span>';
    }

    var falseExpr = this.falseExpr.toHTML(options);
    var falsePrecedence = (0, _operators.getPrecedence)(this.falseExpr, parenthesis);

    if (parenthesis === 'all' || this.falseExpr.type === 'OperatorNode' || falsePrecedence !== null && falsePrecedence <= precedence) {
      falseExpr = '<span class="math-parenthesis math-round-parenthesis">(</span>' + falseExpr + '<span class="math-parenthesis math-round-parenthesis">)</span>';
    }

    return condition + '<span class="math-operator math-conditional-operator">?</span>' + trueExpr + '<span class="math-operator math-conditional-operator">:</span>' + falseExpr;
  };
  /**
   * Get LaTeX representation
   * @param {Object} options
   * @return {string} str
   */


  ConditionalNode.prototype._toTex = function (options) {
    return '\\begin{cases} {' + this.trueExpr.toTex(options) + '}, &\\quad{\\text{if }\\;' + this.condition.toTex(options) + '}\\\\{' + this.falseExpr.toTex(options) + '}, &\\quad{\\text{otherwise}}\\end{cases}';
  };
  /**
   * Test whether a condition is met
   * @param {*} condition
   * @returns {boolean} true if condition is true or non-zero, else false
   */


  function testCondition(condition) {
    if (typeof condition === 'number' || typeof condition === 'boolean' || typeof condition === 'string') {
      return !!condition;
    }

    if (condition) {
      if ((0, _is.isBigNumber)(condition)) {
        return !condition.isZero();
      }

      if ((0, _is.isComplex)(condition)) {
        return !!(condition.re || condition.im);
      }

      if ((0, _is.isUnit)(condition)) {
        return !!condition.value;
      }
    }

    if (condition === null || condition === undefined) {
      return false;
    }

    throw new TypeError('Unsupported type of condition "' + (0, _is.typeOf)(condition) + '"');
  }

  return ConditionalNode;
}, {
  isClass: true,
  isNode: true
});
exports.createConditionalNode = createConditionalNode;