94 lines
2.7 KiB
JavaScript
94 lines
2.7 KiB
JavaScript
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import { getOperator, initOptions } from "./core";
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import { Cursor } from "./cursor";
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import { assert, cloneDeep, isObject, isOperator, normalize } from "./util";
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const TOP_LEVEL_OPS = new Set(
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Array.from(["$and", "$or", "$nor", "$expr", "$jsonSchema"])
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);
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class Query {
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#compiled;
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#options;
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#condition;
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constructor(condition, options) {
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this.#condition = cloneDeep(condition);
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this.#options = initOptions(options);
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this.#compiled = [];
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this.compile();
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}
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compile() {
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assert(
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isObject(this.#condition),
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`query criteria must be an object: ${JSON.stringify(this.#condition)}`
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);
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const whereOperator = {};
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for (const [field, expr] of Object.entries(this.#condition)) {
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if ("$where" === field) {
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assert(
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this.#options.scriptEnabled,
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"$where operator requires 'scriptEnabled' option to be true."
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);
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Object.assign(whereOperator, { field, expr });
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} else if (TOP_LEVEL_OPS.has(field)) {
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this.processOperator(field, field, expr);
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} else {
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assert(!isOperator(field), `unknown top level operator: ${field}`);
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for (const [operator, val] of Object.entries(
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normalize(expr)
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)) {
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this.processOperator(field, operator, val);
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}
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}
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if (whereOperator.field) {
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this.processOperator(
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whereOperator.field,
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whereOperator.field,
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whereOperator.expr
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);
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}
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}
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}
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processOperator(field, operator, value) {
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const call = getOperator("query", operator, this.#options);
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assert(!!call, `unknown query operator ${operator}`);
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this.#compiled.push(call(field, value, this.#options));
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}
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/**
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* Checks if the object passes the query criteria. Returns true if so, false otherwise.
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*
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* @param obj The object to test
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* @returns {boolean}
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*/
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test(obj) {
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return this.#compiled.every((p) => p(obj));
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}
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/**
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* Returns a cursor to select matching documents from the input source.
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*
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* @param source A source providing a sequence of documents
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* @param projection An optional projection criteria
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* @returns {Cursor} A Cursor for iterating over the results
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*/
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find(collection, projection) {
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return new Cursor(
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collection,
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(o) => this.test(o),
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projection || {},
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this.#options
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);
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}
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/**
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* Remove matched documents from the collection returning the remainder
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*
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* @param collection An array of documents
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* @returns {Array} A new array with matching elements removed
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*/
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remove(collection) {
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return collection.reduce((acc, obj) => {
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if (!this.test(obj)) acc.push(obj);
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return acc;
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}, []);
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}
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}
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export {
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Query
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};
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