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28 lines
883 B
JavaScript
28 lines
883 B
JavaScript
"use strict";
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const splitFilter = require("split-filter");
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const operations = require("../operations");
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const NoChange = require("./util/no-change");
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// FIXME: Have some sort of internally-cacheable way to find nodes of a certain type? So that different optimizer visitors don't need to filter the list of clauses over and over again...
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module.exports = {
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name: "collapse-where",
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category: [ "normalization" ],
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visitors: {
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select: ({ collection, clauses }) => {
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let [ whereClauses, otherClauses ] = splitFilter(clauses, (clause) => clause.type === "where");
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if (whereClauses.length > 1) {
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let whereExpressions = whereClauses.map((clause) => clause.expression);
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let newWhere = operations.where(operations.allOf(whereExpressions));
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return operations.select(collection, [ newWhere ].concat(otherClauses));
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} else {
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return NoChange;
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}
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}
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}
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};
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