js-data
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Robust, framework-agnostic in-memory data store.
1,192 lines (1,157 loc) • 38 kB
JavaScript
import utils from './utils'
import Component from './Component'
const DOMAIN = 'Query'
const INDEX_ERR = 'Index inaccessible after first operation'
// Reserved words used by JSData's Query Syntax
const reserved = {
limit: '',
offset: '',
orderBy: '',
skip: '',
sort: '',
where: ''
}
// Used by our JavaScript implementation of the LIKE operator
const escapeRegExp = /([.*+?^=!:${}()|[\]/\\])/g
const percentRegExp = /%/g
const underscoreRegExp = /_/g
const escape = function (pattern) {
return pattern.replace(escapeRegExp, '\\$1')
}
/**
* A class used by the {@link Collection} class to build queries to be executed
* against the collection's data. An instance of `Query` is returned by
* {@link Collection#query}. Query instances are typically short-lived, and you
* shouldn't have to create them yourself. Just use {@link Collection#query}.
*
* ```javascript
* import { Query } from 'js-data';
* ```
*
* @example <caption>Query intro</caption>
* const JSData = require('js-data');
* const { DataStore } = JSData;
* console.log('Using JSData v' + JSData.version.full);
*
* const store = new DataStore();
* store.defineMapper('post');
* const posts = [
* { author: 'John', age: 30, status: 'published', id: 1 },
* { author: 'Sally', age: 31, status: 'draft', id: 2 },
* { author: 'Mike', age: 32, status: 'draft', id: 3 },
* { author: 'Adam', age: 33, status: 'deleted', id: 4 },
* { author: 'Adam', age: 33, status: 'draft', id: 5 }
* ]
* store.add('post', posts);
* const drafts = store.query('post').filter({ status: 'draft' }).limit(2).run();
* console.log(drafts);
*
* @class Query
* @extends Component
* @param {Collection} collection The collection on which this query operates.
* @since 3.0.0
*/
function Query (collection) {
utils.classCallCheck(this, Query)
/**
* The {@link Collection} on which this query operates.
*
* @name Query#collection
* @since 3.0.0
* @type {Collection}
*/
this.collection = collection
/**
* The current data result of this query.
*
* @name Query#data
* @since 3.0.0
* @type {Array}
*/
this.data = null
}
export default Component.extend({
constructor: Query,
_applyWhereFromObject (where) {
const fields = []
const ops = []
const predicates = []
utils.forOwn(where, (clause, field) => {
if (!utils.isObject(clause)) {
clause = {
'==': clause
}
}
utils.forOwn(clause, (expr, op) => {
fields.push(field)
ops.push(op)
predicates.push(expr)
})
})
return {
fields,
ops,
predicates
}
},
_applyWhereFromArray (where) {
const groups = []
where.forEach((_where, i) => {
if (utils.isString(_where)) {
return
}
const prev = where[i - 1]
const parser = utils.isArray(_where) ? this._applyWhereFromArray : this._applyWhereFromObject
const group = parser.call(this, _where)
if (prev === 'or') {
group.isOr = true
}
groups.push(group)
})
groups.isArray = true
return groups
},
_testObjectGroup (keep, first, group, item) {
let i
const fields = group.fields
const ops = group.ops
const predicates = group.predicates
const len = ops.length
for (i = 0; i < len; i++) {
let op = ops[i]
const isOr = op.charAt(0) === '|'
op = isOr ? op.substr(1) : op
const expr = this.evaluate(utils.get(item, fields[i]), op, predicates[i])
if (expr !== undefined) {
keep = first ? expr : (isOr ? keep || expr : keep && expr)
}
first = false
}
return { keep, first }
},
_testArrayGroup (keep, first, groups, item) {
let i
const len = groups.length
for (i = 0; i < len; i++) {
const group = groups[i]
const parser = group.isArray ? this._testArrayGroup : this._testObjectGroup
const result = parser.call(this, true, true, group, item)
if (groups[i - 1]) {
if (group.isOr) {
keep = keep || result.keep
} else {
keep = keep && result.keep
}
} else {
keep = result.keep
}
first = result.first
}
return { keep, first }
},
/**
* Find all entities between two boundaries.
*
* @example <caption>Get the users ages 18 to 30.</caption>
* const JSData = require('js-data');
* const { DataStore } = JSData;
* console.log('Using JSData v' + JSData.version.full);
*
* const store = new DataStore();
* store.defineMapper('user');
* const users = [
* { name: 'Peter', age: 25, id: 1 },
* { name: 'Jim', age: 19, id: 2 },
* { name: 'Mike', age: 17, id: 3 },
* { name: 'Alan', age: 29, id: 4 },
* { name: 'Katie', age: 33, id: 5 }
* ];
* store.add('user', users)
* const filteredUsers = store
* .query('user')
* .between(18, 30, { index: 'age' })
* .run();
* console.log(filteredUsers);
*
* @example <caption>Same as above.</caption>
* const JSData = require('js-data');
* const { DataStore } = JSData;
* console.log('Using JSData v' + JSData.version.full);
*
* const store = new DataStore();
* store.defineMapper('user');
* const users = [
* { name: 'Peter', age: 25, id: 1 },
* { name: 'Jim', age: 19, id: 2 },
* { name: 'Mike', age: 17, id: 3 },
* { name: 'Alan', age: 29, id: 4 },
* { name: 'Katie', age: 33, id: 5 }
* ];
* store.add('user', users)
* const filteredUsers = store
* .query('user')
* .between([18], [30], { index: 'age' })
* .run();
* console.log(filteredUsers);
*
* @method Query#between
* @param {array} leftKeys Keys defining the left boundary.
* @param {array} rightKeys Keys defining the right boundary.
* @param {object} [opts] Configuration options.
* @param {string} [opts.index] Name of the secondary index to use in the
* query. If no index is specified, the main index is used.
* @param {boolean} [opts.leftInclusive=true] Whether to include entities
* on the left boundary.
* @param {boolean} [opts.rightInclusive=false] Whether to include entities
* on the left boundary.
* @param {boolean} [opts.limit] Limit the result to a certain number.
* @param {boolean} [opts.offset] The number of resulting entities to skip.
* @returns {Query} A reference to itself for chaining.
* @since 3.0.0
*/
between (leftKeys, rightKeys, opts) {
opts || (opts = {})
if (this.data) {
throw utils.err(`${DOMAIN}#between`)(500, 'Cannot access index')
}
this.data = this.collection.getIndex(opts.index).between(leftKeys, rightKeys, opts)
return this
},
/**
* The comparison function used by the {@link Query} class.
*
* @method Query#compare
* @param {array} orderBy An orderBy clause used for sorting and sub-sorting.
* @param {number} index The index of the current orderBy clause being used.
* @param {*} a The first item in the comparison.
* @param {*} b The second item in the comparison.
* @returns {number} -1 if `b` should preceed `a`. 0 if `a` and `b` are equal.
* 1 if `a` should preceed `b`.
* @since 3.0.0
*/
compare (orderBy, index, a, b) {
const def = orderBy[index]
let cA = utils.get(a, def[0])
let cB = utils.get(b, def[0])
if (cA && utils.isString(cA)) {
cA = cA.toUpperCase()
}
if (cB && utils.isString(cB)) {
cB = cB.toUpperCase()
}
if (a === undefined) {
a = null
}
if (b === undefined) {
b = null
}
if (def[1].toUpperCase() === 'DESC') {
const temp = cB
cB = cA
cA = temp
}
if (cA < cB) {
return -1
} else if (cA > cB) {
return 1
} else {
if (index < orderBy.length - 1) {
return this.compare(orderBy, index + 1, a, b)
} else {
return 0
}
}
},
/**
* Predicate evaluation function used by the {@link Query} class.
*
* @method Query#evaluate
* @param {*} value The value to evaluate.
* @param {string} op The operator to use in this evaluation.
* @param {*} predicate The predicate to use in this evaluation.
* @returns {boolean} Whether the value passed the evaluation or not.
* @since 3.0.0
*/
evaluate (value, op, predicate) {
const ops = this.constructor.ops
if (ops[op]) {
return ops[op](value, predicate)
}
if (op.indexOf('like') === 0) {
return this.like(predicate, op.substr(4)).exec(value) !== null
} else if (op.indexOf('notLike') === 0) {
return this.like(predicate, op.substr(7)).exec(value) === null
}
},
/**
* Find the record or records that match the provided query or are accepted by
* the provided filter function.
*
* @example <caption>Get the draft posts by authors younger than 30</caption>
* const JSData = require('js-data');
* const { DataStore } = JSData;
* console.log('Using JSData v' + JSData.version.full);
*
* const store = new DataStore();
* store.defineMapper('post')
* const posts = [
* { author: 'John', age: 30, status: 'published', id: 1 },
* { author: 'Sally', age: 31, status: 'published', id: 2 },
* { author: 'Mike', age: 32, status: 'draft', id: 3 },
* { author: 'Adam', age: 33, status: 'deleted', id: 4 },
* { author: 'Adam', age: 33, status: 'published', id: 5 }
* { author: 'Peter', age: 25, status: 'deleted', id: 6 },
* { author: 'Sally', age: 21, status: 'draft', id: 7 },
* { author: 'Jim', age: 27, status: 'draft', id: 8 },
* { author: 'Jim', age: 27, status: 'published', id: 9 },
* { author: 'Jason', age: 55, status: 'published', id: 10 }
* ];
* store.add('post', posts);
* const results = store
* .query('post')
* .filter({
* where: {
* status: {
* '==': 'draft'
* },
* age: {
* '<': 30
* }
* }
* })
* .run();
* console.log(results);
*
* @example <caption>Use a custom filter function</caption>
* const posts = query
* .filter(function (post) {
* return post.isReady();
* })
* .run();
*
* @method Query#filter
* @param {(Object|Function)} [queryOrFn={}] Selection query or filter
* function.
* @param {Function} [thisArg] Context to which to bind `queryOrFn` if
* `queryOrFn` is a function.
* @returns {Query} A reference to itself for chaining.
* @since 3.0.0
*/
filter (query, thisArg) {
/**
* Selection query as defined by JSData's [Query Syntax][querysyntax].
*
* [querysyntax]: http://www.js-data.io/v3.0/docs/query-syntax
*
* @example <caption>Empty "findAll" query</caption>
* const JSData = require('js-data');
* const { DataStore } = JSData;
* console.log('Using JSData v' + JSData.version.full);
*
* const store = new DataStore();
* store.defineMapper('post')
* store.findAll('post').then((posts) => {
* console.log(posts); // [...]
* });
*
* @example <caption>Empty "filter" query</caption>
* const JSData = require('js-data');
* const { DataStore } = JSData;
* console.log('Using JSData v' + JSData.version.full);
*
* const store = new DataStore();
* store.defineMapper('post');
* const posts = store.filter('post');
* console.log(posts); // [...]
*
* @example <caption>Complex "filter" query</caption>
* const JSData = require('js-data');
* const { DataStore } = JSData;
* console.log('Using JSData v' + JSData.version.full);
*
* const store = new DataStore();
* const PAGE_SIZE = 2;
* let currentPage = 3;
*
* store.defineMapper('post');
* const posts = [
* { author: 'John', age: 30, status: 'published', id: 1 },
* { author: 'Sally', age: 31, status: 'published', id: 2 },
* { author: 'Mike', age: 32, status: 'draft', id: 3 },
* { author: 'Adam', age: 33, status: 'deleted', id: 4 },
* { author: 'Adam', age: 33, status: 'published', id: 5 }
* { author: 'Peter', age: 25, status: 'deleted', id: 6 },
* { author: 'Sally', age: 21, status: 'draft', id: 7 },
* { author: 'Jim', age: 27, status: 'draft', id: 8 },
* { author: 'Jim', age: 27, status: 'published', id: 9 },
* { author: 'Jason', age: 55, status: 'published', id: 10 }
* ];
* store.add('post', posts);
* // Retrieve a filtered page of blog posts
* // Would typically replace filter with findAll
* const results = store.filter('post', {
* where: {
* status: {
* // WHERE status = 'published'
* '==': 'published'
* },
* author: {
* // AND author IN ('bob', 'alice')
* 'in': ['bob', 'alice'],
* // OR author IN ('karen')
* '|in': ['karen']
* }
* },
* orderBy: [
* // ORDER BY date_published DESC,
* ['date_published', 'DESC'],
* // ORDER BY title ASC
* ['title', 'ASC']
* ],
* // LIMIT 2
* limit: PAGE_SIZE,
* // SKIP 4
* offset: PAGE_SIZE * (currentPage - 1)
* });
* console.log(results);
*
* @namespace query
* @property {number} [limit] See {@link query.limit}.
* @property {number} [offset] See {@link query.offset}.
* @property {string|Array[]} [orderBy] See {@link query.orderBy}.
* @property {number} [skip] Alias for {@link query.offset}.
* @property {string|Array[]} [sort] Alias for {@link query.orderBy}.
* @property {Object} [where] See {@link query.where}.
* @since 3.0.0
* @tutorial ["http://www.js-data.io/v3.0/docs/query-syntax","JSData's Query Syntax"]
*/
query || (query = {})
this.getData()
if (utils.isObject(query)) {
let where = {}
/**
* Filtering criteria. Records that do not meet this criteria will be exluded
* from the result.
*
* @example <caption>Return posts where author is at least 32 years old</caption>
* const JSData = require('js-data');
* const { DataStore } = JSData;
* console.log('Using JSData v' + JSData.version.full);
*
* const store = new DataStore();
* store.defineMapper('post')
* const posts = [
* { author: 'John', age: 30, id: 5 },
* { author: 'Sally', age: 31, id: 6 },
* { author: 'Mike', age: 32, id: 7 },
* { author: 'Adam', age: 33, id: 8 },
* { author: 'Adam', age: 33, id: 9 }
* ];
* store.add('post', posts);
* const results = store.filter('post', {
* where: {
* age: {
* '>=': 30
* }
* }
* });
* console.log(results);
*
* @name query.where
* @type {Object}
* @see http://www.js-data.io/v3.0/docs/query-syntax
* @since 3.0.0
*/
if (utils.isObject(query.where) || utils.isArray(query.where)) {
where = query.where
}
utils.forOwn(query, function (value, key) {
if (!(key in reserved) && !(key in where)) {
where[key] = {
'==': value
}
}
})
let groups
// Apply filter for each field
if (utils.isObject(where) && Object.keys(where).length !== 0) {
groups = this._applyWhereFromArray([where])
} else if (utils.isArray(where)) {
groups = this._applyWhereFromArray(where)
}
if (groups) {
this.data = this.data.filter((item, i) => this._testArrayGroup(true, true, groups, item).keep)
}
// Sort
let orderBy = query.orderBy || query.sort
if (utils.isString(orderBy)) {
orderBy = [
[orderBy, 'ASC']
]
}
if (!utils.isArray(orderBy)) {
orderBy = null
}
/**
* Determines how records should be ordered in the result.
*
* @example <caption>Order posts by `author` then by `id` descending </caption>
* const JSData = require('js-data');
* const { DataStore } = JSData;
* console.log('Using JSData v' + JSData.version.full);
*
* const store = new DataStore();
* store.defineMapper('post')
* const posts = [
* { author: 'John', age: 30, id: 5 },
* { author: 'Sally', age: 31, id: 6 },
* { author: 'Mike', age: 32, id: 7 },
* { author: 'Adam', age: 33, id: 8 },
* { author: 'Adam', age: 33, id: 9 }
* ];
* store.add('post', posts);
* const results = store.filter('post', {
* orderBy:[['author','ASC'],['id','DESC']]
* });
* console.log(results);
*
* @name query.orderBy
* @type {string|Array[]}
* @see http://www.js-data.io/v3.0/docs/query-syntax
* @since 3.0.0
*/
if (orderBy) {
const index = 0
orderBy.forEach(function (def, i) {
if (utils.isString(def)) {
orderBy[i] = [def, 'ASC']
}
})
this.data.sort((a, b) => this.compare(orderBy, index, a, b))
}
/**
* Number of records to skip.
*
* @example <caption>Retrieve the first "page" of blog posts using findAll</caption>
* const JSData = require('js-data');
* const { DataStore } = JSData;
* console.log('Using JSData v' + JSData.version.full);
*
* const store = new DataStore();
* store.defineMapper('post');
* const PAGE_SIZE = 10;
* let currentPage = 1;
* store.findAll('post', {
* offset: PAGE_SIZE * (currentPage 1)
* limit: PAGE_SIZE
* });
*
* @example <caption>Retrieve the last "page" of blog posts using filter</caption>
* const JSData = require('js-data');
* const { DataStore } = JSData;
* console.log('Using JSData v' + JSData.version.full);
*
* const store = new DataStore();
*
* const PAGE_SIZE = 5;
* let currentPage = 2;
* store.defineMapper('post');
* const posts = [
* { author: 'John', age: 30, id: 1 },
* { author: 'Sally', age: 31, id: 2 },
* { author: 'Mike', age: 32, id: 3 },
* { author: 'Adam', age: 33, id: 4 },
* { author: 'Adam', age: 33, id: 5 },
* { author: 'Peter', age: 25, id: 6 },
* { author: 'Sally', age: 21, id: 7 },
* { author: 'Jim', age: 27, id: 8 },
* { author: 'Jim', age: 27, id: 9 },
* { author: 'Jason', age: 55, id: 10 }
* ];
* store.add('post', posts);
* const results = store.filter('post', {
* offset: PAGE_SIZE * (currentPage 1)
* limit: PAGE_SIZE
* });
* console.log(results)
*
* @name query.offset
* @type {number}
* @see http://www.js-data.io/v3.0/docs/query-syntax
* @since 3.0.0
*/
if (utils.isNumber(query.skip)) {
this.skip(query.skip)
} else if (utils.isNumber(query.offset)) {
this.skip(query.offset)
}
/**
* Maximum number of records to retrieve.
*
* @example <caption>Retrieve the first "page" of blog posts using findAll</caption>
* const JSData = require('js-data');
* const { DataStore } = JSData;
* console.log('Using JSData v' + JSData.version.full);
*
* const store = new DataStore();
* store.defineMapper('post');
*
* const PAGE_SIZE = 10
* let currentPage = 1
* store.findAll('post', {
* offset: PAGE_SIZE * (currentPage 1)
* limit: PAGE_SIZE
* });
*
* @example <caption>Retrieve the last "page" of blog posts using filter</caption>
* const JSData = require('js-data');
* const { DataStore } = JSData;
* console.log('Using JSData v' + JSData.version.full);
*
* const store = new DataStore();
*
* const PAGE_SIZE = 5
* let currentPage = 2
* store.defineMapper('post')
* const posts = [
* { author: 'John', age: 30, id: 1 },
* { author: 'Sally', age: 31, id: 2 },
* { author: 'Mike', age: 32, id: 3 },
* { author: 'Adam', age: 33, id: 4 },
* { author: 'Adam', age: 33, id: 5 },
* { author: 'Peter', age: 25, id: 6 },
* { author: 'Sally', age: 21, id: 7 },
* { author: 'Jim', age: 27, id: 8 },
* { author: 'Jim', age: 27, id: 9 },
* { author: 'Jason', age: 55, id: 10 }
* ];
* store.add('post', posts);
* const results = store.filter('post', {
* offset: PAGE_SIZE * (currentPage 1)
* limit: PAGE_SIZE
* });
* console.log(results)
*
* @name query.limit
* @type {number}
* @see http://www.js-data.io/v3.0/docs/query-syntax
* @since 3.0.0
*/
if (utils.isNumber(query.limit)) {
this.limit(query.limit)
}
} else if (utils.isFunction(query)) {
this.data = this.data.filter(query, thisArg)
}
return this
},
/**
* Iterate over all entities.
*
* @method Query#forEach
* @param {Function} forEachFn Iteration function.
* @param {*} [thisArg] Context to which to bind `forEachFn`.
* @returns {Query} A reference to itself for chaining.
* @since 3.0.0
*/
forEach (forEachFn, thisArg) {
this.getData().forEach(forEachFn, thisArg)
return this
},
/**
* Find the entity or entities that match the provided key.
*
* @example <caption>Get the entity whose primary key is 25.</caption>
* const entities = query.get(25).run();
*
* @example <caption>Same as above.</caption>
* const entities = query.get([25]).run();
*
* @example <caption>Get all users who are active and have the "admin" role.</caption>
* const activeAdmins = query.get(['active', 'admin'], {
* index: 'activityAndRoles'
* }).run();
*
* @example <caption>Get all entities that match a certain weather condition.</caption>
* const niceDays = query.get(['sunny', 'humid', 'calm'], {
* index: 'weatherConditions'
* }).run();
*
* @method Query#get
* @param {array} keyList Key(s) defining the entity to retrieve. If
* `keyList` is not an array (i.e. for a single-value key), it will be
* wrapped in an array.
* @param {object} [opts] Configuration options.
* @param {string} [opts.string] Name of the secondary index to use in the
* query. If no index is specified, the main index is used.
* @returns {Query} A reference to itself for chaining.
* @since 3.0.0
*/
get (keyList, opts) {
keyList || (keyList = [])
opts || (opts = {})
if (this.data) {
throw utils.err(`${DOMAIN}#get`)(500, INDEX_ERR)
}
if (keyList && !utils.isArray(keyList)) {
keyList = [keyList]
}
if (!keyList.length) {
this.getData()
return this
}
this.data = this.collection.getIndex(opts.index).get(keyList)
return this
},
/**
* Find the entity or entities that match the provided keyLists.
*
* @example <caption>Get the posts where "status" is "draft" or "inReview".</caption>
* const posts = query.getAll('draft', 'inReview', { index: 'status' }).run();
*
* @example <caption>Same as above.</caption>
* const posts = query.getAll(['draft'], ['inReview'], { index: 'status' }).run();
*
* @method Query#getAll
* @param {...Array} [keyList] Provide one or more keyLists, and all
* entities matching each keyList will be retrieved. If no keyLists are
* provided, all entities will be returned.
* @param {object} [opts] Configuration options.
* @param {string} [opts.index] Name of the secondary index to use in the
* query. If no index is specified, the main index is used.
* @returns {Query} A reference to itself for chaining.
* @since 3.0.0
*/
getAll (...args) {
let opts = {}
if (this.data) {
throw utils.err(`${DOMAIN}#getAll`)(500, INDEX_ERR)
}
if (!args.length || (args.length === 1 && utils.isObject(args[0]))) {
this.getData()
return this
} else if (args.length && utils.isObject(args[args.length - 1])) {
opts = args[args.length - 1]
args.pop()
}
const collection = this.collection
const index = collection.getIndex(opts.index)
this.data = []
args.forEach((keyList) => {
this.data = this.data.concat(index.get(keyList))
})
return this
},
/**
* Return the current data result of this query.
*
* @method Query#getData
* @returns {Array} The data in this query.
* @since 3.0.0
*/
getData () {
if (!this.data) {
this.data = this.collection.index.getAll()
}
return this.data
},
/**
* Implementation used by the `like` operator. Takes a pattern and flags and
* returns a `RegExp` instance that can test strings.
*
* @method Query#like
* @param {string} pattern Testing pattern.
* @param {string} flags Flags for the regular expression.
* @returns {RegExp} Regular expression for testing strings.
* @since 3.0.0
*/
like (pattern, flags) {
return new RegExp(`^${(escape(pattern).replace(percentRegExp, '.*').replace(underscoreRegExp, '.'))}$`, flags)
},
/**
* Limit the result.
*
* @example <caption>Get only the first 2 posts.</caption>
* const store = new JSData.DataStore();
* store.defineMapper('post');
* const posts = [
* { author: 'John', age: 30, status: 'published', id: 1 },
* { author: 'Sally', age: 31, status: 'draft', id: 2 },
* { author: 'Mike', age: 32, status: 'draft', id: 3 },
* { author: 'Adam', age: 33, status: 'deleted', id: 4 },
* { author: 'Adam', age: 33, status: 'draft', id: 5 }
* ];
* store.add('post', posts);
* const results = store.query('post').limit(2).run();
* console.log(results);
*
* @method Query#limit
* @param {number} num The maximum number of entities to keep in the result.
* @returns {Query} A reference to itself for chaining.
* @since 3.0.0
*/
limit (num) {
if (!utils.isNumber(num)) {
throw utils.err(`${DOMAIN}#limit`, 'num')(400, 'number', num)
}
const data = this.getData()
this.data = data.slice(0, Math.min(data.length, num))
return this
},
/**
* Apply a mapping function to the result data.
*
* @example
* const JSData = require('js-data');
* const { DataStore } = JSData;
* console.log('Using JSData v' + JSData.version.full);
*
* const store = new DataStore();
* store.defineMapper('user');
* const users = [
* { name: 'Peter', age: 25, id: 1 },
* { name: 'Jim', age: 19, id: 2 },
* { name: 'Mike', age: 17, id: 3 },
* { name: 'Alan', age: 29, id: 4 },
* { name: 'Katie', age: 33, id: 5 }
* ];
* store.add('user', users);
* const ages = store
* .query('user')
* .map(function (user) {
* return user.age;
* })
* .run();
* console.log(ages);
*
* @method Query#map
* @param {Function} mapFn Mapping function.
* @param {*} [thisArg] Context to which to bind `mapFn`.
* @returns {Query} A reference to itself for chaining.
* @since 3.0.0
*/
map (mapFn, thisArg) {
this.data = this.getData().map(mapFn, thisArg)
return this
},
/**
* Return the result of calling the specified function on each item in this
* collection's main index.
*
* @example
* const stringAges = UserCollection.query().mapCall('toString').run();
*
* @method Query#mapCall
* @param {string} funcName Name of function to call
* @parama {...*} [args] Remaining arguments to be passed to the function.
* @returns {Query} A reference to itself for chaining.
* @since 3.0.0
*/
mapCall (funcName, ...args) {
this.data = this.getData().map(function (item) {
return item[funcName](...args)
})
return this
},
/**
* Complete the execution of the query and return the resulting data.
*
* @method Query#run
* @returns {Array} The result of executing this query.
* @since 3.0.0
*/
run () {
const data = this.data
this.data = null
return data
},
/**
* Skip a number of results.
*
* @example <caption>Get all but the first 2 posts.</caption>
* const JSData = require('js-data');
* const { DataStore } = JSData;
* console.log('Using JSData v' + JSData.version.full);
*
* const store = new DataStore();
* store.defineMapper('post');
* const posts = [
* { author: 'John', age: 30, status: 'published', id: 1 },
* { author: 'Sally', age: 31, status: 'draft', id: 2 },
* { author: 'Mike', age: 32, status: 'draft', id: 3 },
* { author: 'Adam', age: 33, status: 'deleted', id: 4 },
* { author: 'Adam', age: 33, status: 'draft', id: 5 }
* ];
* store.add('post', posts);
* const results = store.query('post').skip(2).run();
* console.log(results);
*
* @method Query#skip
* @param {number} num The number of entities to skip.
* @returns {Query} A reference to itself for chaining.
* @since 3.0.0
*/
skip (num) {
if (!utils.isNumber(num)) {
throw utils.err(`${DOMAIN}#skip`, 'num')(400, 'number', num)
}
const data = this.getData()
if (num < data.length) {
this.data = data.slice(num)
} else {
this.data = []
}
return this
}
}, {
/**
* The filtering operators supported by {@link Query#filter}, and which are
* implemented by adapters (for the most part).
*
* @example <caption>Variant 1</caption>
* const JSData = require('js-data');
* const { DataStore } = JSData;
* console.log('Using JSData v' + JSData.version.full);
*
* const store = new DataStore();
* store.defineMapper('post');
* const posts = [
* { author: 'John', age: 30, status: 'published', id: 1 },
* { author: 'Sally', age: 31, status: 'published', id: 2 },
* { author: 'Mike', age: 32, status: 'published', id: 3 },
* { author: 'Adam', age: 33, status: 'deleted', id: 4 },
* { author: 'Adam', age: 33, status: 'published', id: 5 }
* ];
* store.add('post', posts);
* const publishedPosts = store.filter('post', {
* status: 'published',
* limit: 2
* });
* console.log(publishedPosts);
*
*
* @example <caption>Variant 2</caption>
* const JSData = require('js-data');
* const { DataStore } = JSData;
* console.log('Using JSData v' + JSData.version.full);
*
* const store = new DataStore();
* store.defineMapper('post')
* const posts = [
* { author: 'John', age: 30, status: 'published', id: 1 },
* { author: 'Sally', age: 31, status: 'published', id: 2 },
* { author: 'Mike', age: 32, status: 'published', id: 3 },
* { author: 'Adam', age: 33, status: 'deleted', id: 4 },
* { author: 'Adam', age: 33, status: 'published', id: 5 }
* ];
* store.add('post', posts);
* const publishedPosts = store.filter('post', {
* where: {
* status: {
* '==': 'published'
* }
* },
* limit: 2
* });
* console.log(publishedPosts);
*
* @example <caption>Variant 3</caption>
* const JSData = require('js-data');
* const { DataStore } = JSData;
* console.log('Using JSData v' + JSData.version.full);
*
* const store = new DataStore();
* store.defineMapper('post');
* const posts = [
* { author: 'John', age: 30, status: 'published', id: 1 },
* { author: 'Sally', age: 31, status: 'published', id: 2 },
* { author: 'Mike', age: 32, status: 'published', id: 3 },
* { author: 'Adam', age: 33, status: 'deleted', id: 4 },
* { author: 'Adam', age: 33, status: 'published', id: 5 }
* ];
* store.add('post', posts);
* const publishedPosts = store
* .query('post')
* .filter({ status: 'published' })
* .limit(2)
* .run();
* console.log(publishedPosts);
*
* @example <caption>Variant 4</caption>
* const JSData = require('js-data');
* const { DataStore } = JSData;
* console.log('Using JSData v' + JSData.version.full);
*
* const store = new DataStore();
* store.defineMapper('post');
* const posts = [
* { author: 'John', age: 30, status: 'published', id: 1 },
* { author: 'Sally', age: 31, status: 'published', id: 2 },
* { author: 'Mike', age: 32, status: 'published', id: 3 },
* { author: 'Adam', age: 33, status: 'deleted', id: 4 },
* { author: 'Adam', age: 33, status: 'published', id: 5 }
* ];
* store.add('post', posts);
* const publishedPosts = store
* .query('post')
* .filter({
* where: {
* status: {
* '==': 'published'
* }
* }
* })
* .limit(2)
* .run();
* console.log(publishedPosts);
*
* @example <caption>Multiple operators</caption>
* const JSData = require('js-data');
* const { DataStore } = JSData;
* console.log('Using JSData v' + JSData.version.full);
*
* const store = new DataStore();
* store.defineMapper('post');
* const posts = [
* { author: 'John', age: 30, status: 'published', id: 1 },
* { author: 'Sally', age: 31, status: 'published', id: 2 },
* { author: 'Mike', age: 32, status: 'published', id: 3 },
* { author: 'Adam', age: 33, status: 'deleted', id: 4 },
* { author: 'Adam', age: 33, status: 'published', id: 5 }
* ];
* store.add('post', posts);
*
* const myPublishedPosts = store.filter('post', {
* where: {
* status: {
* '==': 'published'
* },
* user_id: {
* '==': currentUser.id
* }
* }
* });
*
* console.log(myPublishedPosts);
*
* @name Query.ops
* @property {Function} == Equality operator.
* @property {Function} != Inequality operator.
* @property {Function} > Greater than operator.
* @property {Function} >= Greater than (inclusive) operator.
* @property {Function} < Less than operator.
* @property {Function} <= Less than (inclusive) operator.
* @property {Function} isectEmpty Operator that asserts that the intersection
* between two arrays is empty.
* @property {Function} isectNotEmpty Operator that asserts that the
* intersection between two arrays is __not__ empty.
* @property {Function} in Operator that asserts whether a value is in an
* array.
* @property {Function} notIn Operator that asserts whether a value is __not__
* in an array.
* @property {Function} contains Operator that asserts whether an array
* contains a value.
* @property {Function} notContains Operator that asserts whether an array
* does __not__ contain a value.
* @since 3.0.0
* @type {Object}
*/
ops: {
'=': function (value, predicate) {
return value == predicate // eslint-disable-line
},
'==': function (value, predicate) {
return value == predicate // eslint-disable-line
},
'===': function (value, predicate) {
return value === predicate
},
'!=': function (value, predicate) {
return value != predicate // eslint-disable-line
},
'!==': function (value, predicate) {
return value !== predicate
},
'>': function (value, predicate) {
return value > predicate
},
'>=': function (value, predicate) {
return value >= predicate
},
'<': function (value, predicate) {
return value < predicate
},
'<=': function (value, predicate) {
return value <= predicate
},
isectEmpty: function (value, predicate) {
return !utils.intersection((value || []), (predicate || [])).length
},
isectNotEmpty: function (value, predicate) {
return utils.intersection((value || []), (predicate || [])).length
},
in: function (value, predicate) {
return predicate.indexOf(value) !== -1
},
notIn: function (value, predicate) {
return predicate.indexOf(value) === -1
},
contains: function (value, predicate) {
return (value || []).indexOf(predicate) !== -1
},
notContains: function (value, predicate) {
return (value || []).indexOf(predicate) === -1
}
}
})
/**
* Create a subclass of this Query:
* @example <caption>Query.extend</caption>
* const JSData = require('js-data');
* const { Query } = JSData;
* console.log('Using JSData v' + JSData.version.full);
*
* // Extend the class using ES2015 class syntax.
* class CustomQueryClass extends Query {
* foo () { return 'bar'; }
* static beep () { return 'boop'; }
* }
* const customQuery = new CustomQueryClass();
* console.log(customQuery.foo());
* console.log(CustomQueryClass.beep());
*
* // Extend the class using alternate method.
* const OtherQueryClass = Query.extend({
* foo () { return 'bar'; }
* }, {
* beep () { return 'boop'; }
* });
* const otherQuery = new OtherQueryClass();
* console.log(otherQuery.foo());
* console.log(OtherQueryClass.beep());
*
* // Extend the class, providing a custom constructor.
* function AnotherQueryClass (collection) {
* Query.call(this, collection);
* this.created_at = new Date().getTime();
* }
* Query.extend({
* constructor: AnotherQueryClass,
* foo () { return 'bar'; }
* }, {
* beep () { return 'boop'; }
* });
* const anotherQuery = new AnotherQueryClass();
* console.log(anotherQuery.created_at);
* console.log(anotherQuery.foo());
* console.log(AnotherQueryClass.beep());
*
* @method Query.extend
* @param {object} [props={}] Properties to add to the prototype of the
* subclass.
* @param {object} [props.constructor] Provide a custom constructor function
* to be used as the subclass itself.
* @param {object} [classProps={}] Static properties to add to the subclass.
* @returns {Constructor} Subclass of this Query class.
* @since 3.0.0
*/