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.
*
* ```javascript
* import {Query} from 'js-data'
* ```
*
* @class Query
* @extends Component
* @param {Collection} collection The collection on which this query operates.
*/
export default Component.extend({
constructor: function Query (collection) {
const self = this
utils.classCallCheck(self, Query)
/**
* The {@link Collection} on which this query operates.
*
* @name Query#collection
* @type {Collection}
*/
self.collection = collection
/**
* The current data result of this query.
*
* @name Query#data
* @type {Array}
*/
self.data = null
},
/**
* Find all entities between two boundaries.
*
* Get the users ages 18 to 30
* ```js
* const users = query.between(18, 30, { index: 'age' }).run()
* ```
* Same as above
* ```js
* const users = query.between([18], [30], { index: 'age' }).run()
* ```
*
* @name Query#between
* @method
* @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.
* @return {Query} A reference to itself for chaining.
*/
between (leftKeys, rightKeys, opts) {
const self = this
opts || (opts = {})
if (self.data) {
throw utils.err(`${DOMAIN}#between`)(500, 'Cannot access index')
}
self.data = self.collection.getIndex(opts.index).between(leftKeys, rightKeys, opts)
return self
},
/**
* The comparison function used by the Query class.
*
* @name Query#compare
* @method
* @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.
* @return {number} -1 if `b` should preceed `a`. 0 if `a` and `b` are equal.
* 1 if `a` should preceed `b`.
*/
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 Query class.
*
* @name Query#evaluate
* @method
* @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.
* @return {boolean} Whether the value passed the evaluation or not.
*/
evaluate (value, op, predicate) {
const ops = this.constructor.ops
if (ops[op]) {
return ops[op](value, predicate)
}
if (op.indexOf('like') === 0) {
return !utils.isNull(this.like(predicate, op.substr(4)).exec(value))
} else if (op.indexOf('notLike') === 0) {
return utils.isNull(this.like(predicate, op.substr(7)).exec(value))
}
},
/**
* Find the entity or entities that match the provided query or pass the
* provided filter function.
*
* #### Example
*
* Get the draft posts created less than three months
* ```js
* const posts = query.filter({
* where: {
* status: {
* '==': 'draft'
* },
* created_at_timestamp: {
* '>=': (new Date().getTime() - (1000 * 60 * 60 * 24 * 30 * 3)) // 3 months ago
* }
* }
* }).run()
* ```
* Use a custom filter function
* ```js
* const posts = query.filter(function (post) {
* return post.isReady()
* }).run()
* ```
*
* @name Query#filter
* @method
* @param {(Object|Function)} [queryOrFn={}] - Selection query or filter
* function.
* @param {Function} [thisArg] - Context to which to bind `queryOrFn` if
* `queryOrFn` is a function.
* @return {Query} A reference to itself for chaining.
*/
filter (query, thisArg) {
const self = this
query || (query = {})
self.getData()
if (utils.isObject(query)) {
let where = {}
// Filter
if (utils.isObject(query.where)) {
where = query.where
}
utils.forOwn(query, function (value, key) {
if (!(key in reserved) && !(key in where)) {
where[key] = {
'==': value
}
}
})
const fields = []
const ops = []
const predicates = []
utils.forOwn(where, function (clause, field) {
if (!utils.isObject(clause)) {
clause = {
'==': clause
}
}
utils.forOwn(clause, function (expr, op) {
fields.push(field)
ops.push(op)
predicates.push(expr)
})
})
if (fields.length) {
let i
let len = fields.length
self.data = self.data.filter(function (item) {
let first = true
let keep = true
for (i = 0; i < len; i++) {
let op = ops[i]
const isOr = op.charAt(0) === '|'
op = isOr ? op.substr(1) : op
const expr = self.evaluate(utils.get(item, fields[i]), op, predicates[i])
if (expr !== undefined) {
keep = first ? expr : (isOr ? keep || expr : keep && expr)
}
first = false
}
return keep
})
}
// Sort
let orderBy = query.orderBy || query.sort
if (utils.isString(orderBy)) {
orderBy = [
[orderBy, 'ASC']
]
}
if (!utils.isArray(orderBy)) {
orderBy = null
}
// Apply 'orderBy'
if (orderBy) {
let index = 0
orderBy.forEach(function (def, i) {
if (utils.isString(def)) {
orderBy[i] = [def, 'ASC']
}
})
self.data.sort(function (a, b) {
return self.compare(orderBy, index, a, b)
})
}
// Skip
if (utils.isNumber(query.skip)) {
self.skip(query.skip)
} else if (utils.isNumber(query.offset)) {
self.skip(query.offset)
}
// Limit
if (utils.isNumber(query.limit)) {
self.limit(query.limit)
}
} else if (utils.isFunction(query)) {
self.data = self.data.filter(query, thisArg)
}
return self
},
/**
* Iterate over all entities.
*
* @name Query#forEach
* @method
* @param {Function} forEachFn - Iteration function.
* @param {*} [thisArg] - Context to which to bind `forEachFn`.
* @return {Query} A reference to itself for chaining.
*/
forEach (forEachFn, thisArg) {
this.getData().forEach(forEachFn, thisArg)
return this
},
/**
* Find the entity or entities that match the provided key.
*
* #### Example
*
* Get the entity whose primary key is 25
* ```js
* const entities = query.get(25).run()
* ```
* Same as above
* ```js
* const entities = query.get([25]).run()
* ```
* Get all users who are active and have the "admin" role
* ```js
* const activeAdmins = query.get(['active', 'admin'], {
* index: 'activityAndRoles'
* }).run()
* ```
* Get all entities that match a certain weather condition
* ```js
* const niceDays = query.get(['sunny', 'humid', 'calm'], {
* index: 'weatherConditions'
* }).run()
* ```
*
* @name Query#get
* @method
* @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.
* @return {Query} A reference to itself for chaining.
*/
get (keyList, opts) {
const self = this
keyList || (keyList = [])
opts || (opts = {})
if (self.data) {
throw utils.err(`${DOMAIN}#get`)(500, INDEX_ERR)
}
if (keyList && !utils.isArray(keyList)) {
keyList = [keyList]
}
if (!keyList.length) {
self.getData()
return self
}
self.data = self.collection.getIndex(opts.index).get(keyList)
return self
},
/**
* Find the entity or entities that match the provided keyLists.
*
* #### Example
*
* Get the posts where "status" is "draft" or "inReview"
* ```js
* const posts = query.getAll('draft', 'inReview', { index: 'status' }).run()
* ```
* Same as above
* ```js
* const posts = query.getAll(['draft'], ['inReview'], { index: 'status' }).run()
* ```
*
* @name Query#getAll
* @method
* @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.
* @return {Query} A reference to itself for chaining.
*/
getAll (...args) {
const self = this
let opts = {}
if (self.data) {
throw utils.err(`${DOMAIN}#getAll`)(500, INDEX_ERR)
}
if (!args.length || args.length === 1 && utils.isObject(args[0])) {
self.getData()
return self
} else if (args.length && utils.isObject(args[args.length - 1])) {
opts = args[args.length - 1]
args.pop()
}
const collection = self.collection
const index = collection.getIndex(opts.index)
self.data = []
args.forEach(function (keyList) {
self.data = self.data.concat(index.get(keyList))
})
return self
},
/**
* Return the current data result of this query.
* @name Query#getData
* @method
* @return {Array} The data in this query.
*/
getData () {
const self = this
if (!self.data) {
self.data = self.collection.index.getAll()
}
return self.data
},
like (pattern, flags) {
return new RegExp(`^${(escape(pattern).replace(percentRegExp, '.*').replace(underscoreRegExp, '.'))}$`, flags)
},
/**
* Limit the result.
*
* #### Example
*
* Get only the first 10 draft posts
* ```js
* const posts = query.get('draft', { index: 'status' }).limit(10).run()
* ```
*
* @name Query#limit
* @method
* @param {number} num - The maximum number of entities to keep in the result.
* @return {Query} A reference to itself for chaining.
*/
limit (num) {
if (!utils.isNumber(num)) {
throw utils.err(`${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.
*
* @name Query#map
* @method
* @param {Function} mapFn - Mapping function.
* @param {*} [thisArg] - Context to which to bind `mapFn`.
* @return {Query} A reference to itself for chaining.
*/
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.
* @name Query#mapCall
* @method
* @param {string} funcName - Name of function to call
* @parama {...*} [args] - Remaining arguments to be passed to the function.
* @return {Query} A reference to itself for chaining.
*/
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.
*
* @name Query#run
* @method
* @return {Array} The result of executing this query.
*/
run () {
const data = this.data
this.data = null
return data
},
/**
* Skip a number of results.
*
* #### Example
*
* Get all but the first 10 draft posts
* ```js
* const posts = query.get('draft', { index: 'status' }).skip(10).run()
* ```
*
* @name Query#skip
* @method
* @param {number} num - The number of entities to skip.
* @return {Query} A reference to itself for chaining.
*/
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
}
}, {
/**
* TODO
*
* @name Query.ops
* @type {Object}
*/
ops: {
'==': 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
}
}
})