json-rules-engine
Version:
Rules Engine expressed in simple json
186 lines (156 loc) • 6.86 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", {
value: true
});
var _createClass = function () { function defineProperties(target, props) { for (var i = 0; i < props.length; i++) { var descriptor = props[i]; descriptor.enumerable = descriptor.enumerable || false; descriptor.configurable = true; if ("value" in descriptor) descriptor.writable = true; Object.defineProperty(target, descriptor.key, descriptor); } } return function (Constructor, protoProps, staticProps) { if (protoProps) defineProperties(Constructor.prototype, protoProps); if (staticProps) defineProperties(Constructor, staticProps); return Constructor; }; }();
var _debug = require('./debug');
var _debug2 = _interopRequireDefault(_debug);
var _lodash = require('lodash.isobjectlike');
var _lodash2 = _interopRequireDefault(_lodash);
function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } }
var Condition = function () {
function Condition(properties) {
_classCallCheck(this, Condition);
if (!properties) throw new Error('Condition: constructor options required');
var booleanOperator = Condition.booleanOperator(properties);
Object.assign(this, properties);
if (booleanOperator) {
var subConditions = properties[booleanOperator];
if (!Array.isArray(subConditions)) {
throw new Error('"' + booleanOperator + '" must be an array');
}
this.operator = booleanOperator;
// boolean conditions always have a priority; default 1
this.priority = parseInt(properties.priority, 10) || 1;
this[booleanOperator] = subConditions.map(function (c) {
return new Condition(c);
});
} else {
if (!Object.prototype.hasOwnProperty.call(properties, 'fact')) throw new Error('Condition: constructor "fact" property required');
if (!Object.prototype.hasOwnProperty.call(properties, 'operator')) throw new Error('Condition: constructor "operator" property required');
if (!Object.prototype.hasOwnProperty.call(properties, 'value')) throw new Error('Condition: constructor "value" property required');
// a non-boolean condition does not have a priority by default. this allows
// priority to be dictated by the fact definition
if (Object.prototype.hasOwnProperty.call(properties, 'priority')) {
properties.priority = parseInt(properties.priority, 10);
}
}
}
/**
* Converts the condition into a json-friendly structure
* @param {Boolean} stringify - whether to return as a json string
* @returns {string,object} json string or json-friendly object
*/
_createClass(Condition, [{
key: 'toJSON',
value: function toJSON() {
var stringify = arguments.length > 0 && arguments[0] !== undefined ? arguments[0] : true;
var props = {};
if (this.priority) {
props.priority = this.priority;
}
var oper = Condition.booleanOperator(this);
if (oper) {
props[oper] = this[oper].map(function (c) {
return c.toJSON(stringify);
});
} else {
props.operator = this.operator;
props.value = this.value;
props.fact = this.fact;
if (this.factResult !== undefined) {
props.factResult = this.factResult;
}
if (this.result !== undefined) {
props.result = this.result;
}
if (this.params) {
props.params = this.params;
}
if (this.path) {
props.path = this.path;
}
}
if (stringify) {
return JSON.stringify(props);
}
return props;
}
/**
* Interprets .value as either a primitive, or if a fact, retrieves the fact value
*/
}, {
key: '_getValue',
value: function _getValue(almanac) {
var value = this.value;
if ((0, _lodash2.default)(value) && Object.prototype.hasOwnProperty.call(value, 'fact')) {
// value: { fact: 'xyz' }
return almanac.factValue(value.fact, value.params, value.path);
}
return Promise.resolve(value);
}
/**
* Takes the fact result and compares it to the condition 'value', using the operator
* LHS OPER RHS
* <fact + params + path> <operator> <value>
*
* @param {Almanac} almanac
* @param {Map} operatorMap - map of available operators, keyed by operator name
* @returns {Boolean} - evaluation result
*/
}, {
key: 'evaluate',
value: function evaluate(almanac, operatorMap) {
var _this = this;
if (!almanac) return Promise.reject(new Error('almanac required'));
if (!operatorMap) return Promise.reject(new Error('operatorMap required'));
if (this.isBooleanOperator()) return Promise.reject(new Error('Cannot evaluate() a boolean condition'));
var op = operatorMap.get(this.operator);
if (!op) return Promise.reject(new Error('Unknown operator: ' + this.operator));
return this._getValue(almanac) // todo - parallelize
.then(function (rightHandSideValue) {
return almanac.factValue(_this.fact, _this.params, _this.path).then(function (leftHandSideValue) {
var result = op.evaluate(leftHandSideValue, rightHandSideValue);
(0, _debug2.default)('condition::evaluate <' + leftHandSideValue + ' ' + _this.operator + ' ' + rightHandSideValue + '?> (' + result + ')');
return { result: result, leftHandSideValue: leftHandSideValue, rightHandSideValue: rightHandSideValue, operator: _this.operator };
});
});
}
/**
* Returns the boolean operator for the condition
* If the condition is not a boolean condition, the result will be 'undefined'
* @return {string 'all' or 'any'}
*/
}, {
key: 'booleanOperator',
/**
* Returns the condition's boolean operator
* Instance version of Condition.isBooleanOperator
* @returns {string,undefined} - 'any', 'all', or undefined (if not a boolean condition)
*/
value: function booleanOperator() {
return Condition.booleanOperator(this);
}
/**
* Whether the operator is boolean ('all', 'any')
* @returns {Boolean}
*/
}, {
key: 'isBooleanOperator',
value: function isBooleanOperator() {
return Condition.booleanOperator(this) !== undefined;
}
}], [{
key: 'booleanOperator',
value: function booleanOperator(condition) {
if (Object.prototype.hasOwnProperty.call(condition, 'any')) {
return 'any';
} else if (Object.prototype.hasOwnProperty.call(condition, 'all')) {
return 'all';
}
}
}]);
return Condition;
}();
exports.default = Condition;