47 lines
1.7 KiB
TypeScript
47 lines
1.7 KiB
TypeScript
|
// License: LGPL-3.0-or-later
|
||
|
|
// from https://github.com/mtraynham/lodash-joins/blob/c252b462981562451d85d1e09c8f273ce7fe06c5/lib/hash/hashInnerJoin.ts
|
||
|
|
import groupBy from 'lodash/groupBy';
|
||
|
|
import has from 'lodash/has';
|
||
|
|
import map from 'lodash/map';
|
||
|
|
import reduceRight from 'lodash/reduceRight';
|
||
|
|
|
||
|
|
import {Accessor, Merger} from '../typings';
|
||
|
|
import {toStringAccessor} from './util';
|
||
|
|
|
||
|
|
/**
|
||
|
|
* Hash inner join
|
||
|
|
*/
|
||
|
|
export default function hashInnerJoin<LeftRow, RightRow, Key, MergeResult>(
|
||
|
|
a: LeftRow[],
|
||
|
|
aAccessor: Accessor<LeftRow, Key>,
|
||
|
|
b: RightRow[],
|
||
|
|
bAccessor: Accessor<RightRow, Key>,
|
||
|
|
merger: Merger<LeftRow, RightRow, MergeResult>
|
||
|
|
): MergeResult[] {
|
||
|
|
if (a.length < 1 || b.length < 1) {
|
||
|
|
return [];
|
||
|
|
}
|
||
|
|
const leftAccessor: Accessor<LeftRow, string> = toStringAccessor(aAccessor),
|
||
|
|
rightAccessor: Accessor<RightRow, string> = toStringAccessor(bAccessor);
|
||
|
|
let index: {[key: string]: (LeftRow | RightRow)[]},
|
||
|
|
key: string;
|
||
|
|
if (a.length < b.length) {
|
||
|
|
index = groupBy(a, leftAccessor);
|
||
|
|
return reduceRight(b, (previous: MergeResult[], bDatum: RightRow) => {
|
||
|
|
key = rightAccessor(bDatum);
|
||
|
|
if (has(index, key)) {
|
||
|
|
return map(index[key], (aDatum: LeftRow) => merger(aDatum, bDatum)).concat(previous);
|
||
|
|
}
|
||
|
|
return previous;
|
||
|
|
}, []);
|
||
|
|
}
|
||
|
|
index = groupBy(b, rightAccessor);
|
||
|
|
return reduceRight(a, (previous: MergeResult[], aDatum: LeftRow) => {
|
||
|
|
key = leftAccessor(aDatum);
|
||
|
|
if (has(index, key)) {
|
||
|
|
return map(index[key], (bDatum: RightRow) => merger(aDatum, bDatum)).concat(previous);
|
||
|
|
}
|
||
|
|
return previous;
|
||
|
|
}, []);
|
||
|
|
}
|