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/**
* @filedescription Object Schema
*/
"use strict";
//-----------------------------------------------------------------------------
// Requirements
//-----------------------------------------------------------------------------
const { MergeStrategy } = require("./merge-strategy");
const { ValidationStrategy } = require("./validation-strategy");
//-----------------------------------------------------------------------------
// Private
//-----------------------------------------------------------------------------
const strategies = Symbol("strategies");
const requiredKeys = Symbol("requiredKeys");
/**
* Validates a schema strategy.
* @param {string} name The name of the key this strategy is for.
* @param {Object} strategy The strategy for the object key.
* @param {boolean} [strategy.required=true] Whether the key is required.
* @param {string[]} [strategy.requires] Other keys that are required when
* this key is present.
* @param {Function} strategy.merge A method to call when merging two objects
* with the same key.
* @param {Function} strategy.validate A method to call when validating an
* object with the key.
* @returns {void}
* @throws {Error} When the strategy is missing a name.
* @throws {Error} When the strategy is missing a merge() method.
* @throws {Error} When the strategy is missing a validate() method.
*/
function validateDefinition(name, strategy) {
let hasSchema = false;
if (strategy.schema) {
if (typeof strategy.schema === "object") {
hasSchema = true;
} else {
throw new TypeError("Schema must be an object.");
}
}
if (typeof strategy.merge === "string") {
if (!(strategy.merge in MergeStrategy)) {
throw new TypeError(`Definition for key "${name}" missing valid merge strategy.`);
}
} else if (!hasSchema && typeof strategy.merge !== "function") {
throw new TypeError(`Definition for key "${name}" must have a merge property.`);
}
if (typeof strategy.validate === "string") {
if (!(strategy.validate in ValidationStrategy)) {
throw new TypeError(`Definition for key "${name}" missing valid validation strategy.`);
}
} else if (!hasSchema && typeof strategy.validate !== "function") {
throw new TypeError(`Definition for key "${name}" must have a validate() method.`);
}
}
//-----------------------------------------------------------------------------
// Class
//-----------------------------------------------------------------------------
/**
* Represents an object validation/merging schema.
*/
class ObjectSchema {
/**
* Creates a new instance.
*/
constructor(definitions) {
if (!definitions) {
throw new Error("Schema definitions missing.");
}
/**
* Track all strategies in the schema by key.
* @type {Map}
* @property strategies
*/
this[strategies] = new Map();
/**
* Separately track any keys that are required for faster validation.
* @type {Map}
* @property requiredKeys
*/
this[requiredKeys] = new Map();
// add in all strategies
for (const key of Object.keys(definitions)) {
validateDefinition(key, definitions[key]);
// normalize merge and validate methods if subschema is present
if (typeof definitions[key].schema === "object") {
const schema = new ObjectSchema(definitions[key].schema);
definitions[key] = {
...definitions[key],
merge(first = {}, second = {}) {
return schema.merge(first, second);
},
validate(value) {
ValidationStrategy.object(value);
schema.validate(value);
}
};
}
// normalize the merge method in case there's a string
if (typeof definitions[key].merge === "string") {
definitions[key] = {
...definitions[key],
merge: MergeStrategy[definitions[key].merge]
};
};
// normalize the validate method in case there's a string
if (typeof definitions[key].validate === "string") {
definitions[key] = {
...definitions[key],
validate: ValidationStrategy[definitions[key].validate]
};
};
this[strategies].set(key, definitions[key]);
if (definitions[key].required) {
this[requiredKeys].set(key, definitions[key]);
}
}
}
/**
* Determines if a strategy has been registered for the given object key.
* @param {string} key The object key to find a strategy for.
* @returns {boolean} True if the key has a strategy registered, false if not.
*/
hasKey(key) {
return this[strategies].has(key);
}
/**
* Merges objects together to create a new object comprised of the keys
* of the all objects. Keys are merged based on the each key's merge
* strategy.
* @param {...Object} objects The objects to merge.
* @returns {Object} A new object with a mix of all objects' keys.
* @throws {Error} If any object is invalid.
*/
merge(...objects) {
// double check arguments
if (objects.length < 2) {
throw new Error("merge() requires at least two arguments.");
}
if (objects.some(object => (object == null || typeof object !== "object"))) {
throw new Error("All arguments must be objects.");
}
return objects.reduce((result, object) => {
this.validate(object);
for (const [key, strategy] of this[strategies]) {
try {
if (key in result || key in object) {
const value = strategy.merge.call(this, result[key], object[key]);
if (value !== undefined) {
result[key] = value;
}
}
} catch (ex) {
ex.message = `Key "${key}": ` + ex.message;
throw ex;
}
}
return result;
}, {});
}
/**
* Validates an object's keys based on the validate strategy for each key.
* @param {Object} object The object to validate.
* @returns {void}
* @throws {Error} When the object is invalid.
*/
validate(object) {
// check existing keys first
for (const key of Object.keys(object)) {
// check to see if the key is defined
if (!this.hasKey(key)) {
throw new Error(`Unexpected key "${key}" found.`);
}
// validate existing keys
const strategy = this[strategies].get(key);
// first check to see if any other keys are required
if (Array.isArray(strategy.requires)) {
if (!strategy.requires.every(otherKey => otherKey in object)) {
throw new Error(`Key "${key}" requires keys "${strategy.requires.join("\", \"")}".`);
}
}
// now apply remaining validation strategy
try {
strategy.validate.call(strategy, object[key]);
} catch (ex) {
ex.message = `Key "${key}": ` + ex.message;
throw ex;
}
}
// ensure required keys aren't missing
for (const [key] of this[requiredKeys]) {
if (!(key in object)) {
throw new Error(`Missing required key "${key}".`);
}
}
}
}
exports.ObjectSchema = ObjectSchema;