@miyauci/upsert
v1.2.0
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Maps for emplace, TC39 proposal-upsert implementation
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upsert
Maps for emplace, TC39 proposal-upsert implementation.
Table of Contents
Install
deno.land:
import * as mod from "https://deno.land/x/upsert/mod.ts";
npm:
npm i @miyauci/upsert
Usage
Add a value to a map like if it does not already have something at key
, and
will also update an existing value at key
.
import { emplace } from "https://deno.land/x/upsert/mod.ts";
import { assert } from "https://deno.land/std/testing/asserts.ts";
declare const map: Map<string, number>;
declare const key: string;
const result = emplace(map, key, {
insert: () => 0,
update: (existing) => ++existing,
});
assert(map.has(key));
Insert
Add the entry if the key does not exist.
import { emplace } from "https://deno.land/x/upsert/mod.ts";
import { assert } from "https://deno.land/std/testing/asserts.ts";
import {
assertType,
type IsExact,
} from "https://deno.land/std/testing/types.ts";
declare const map: Map<string, number>;
declare const key: string;
declare const value: number;
const result = emplace(map, key, { insert: () => value });
assert(map.has(key));
assertType<IsExact<typeof result, number>>(true);
Just insert
If only inserting is required, insert
is available.
import { insert } from "https://deno.land/x/upsert/mod.ts";
import { assertEquals } from "https://deno.land/std/testing/asserts.ts";
declare const key: string;
declare const value: number;
const map = new Map<typeof key, typeof value>();
insert(map, key, () => value);
assertEquals(map, new Map([[key, value]]));
Update
Update the entry if the key exists.
import { emplace } from "https://deno.land/x/upsert/mod.ts";
import { assert } from "https://deno.land/std/testing/asserts.ts";
import {
assertType,
type IsExact,
} from "https://deno.land/std/testing/types.ts";
declare const map: Map<string, number>;
declare const key: string;
const result = emplace(map, key, { update: (existing) => ++existing });
assertType<IsExact<typeof result, number | undefined>>(true);
Just update
If only updating is required, update
is available.
import { update } from "https://deno.land/x/upsert/mod.ts";
import { assertEquals } from "https://deno.land/std/testing/asserts.ts";
declare const key: string;
const map = new Map([[key, 0]]);
update(map, key, (existing) => ++existing);
assertEquals(map, new Map([[key, 1]]));
Emplaceable
Mixin for emplace
.
import { emplaceable } from "https://deno.land/x/upsert/mod.ts";
import { assert } from "https://deno.land/std/testing/asserts.ts";
class MyMap extends emplaceable(Map) {}
assert(MyMap.prototype.emplace);
decorator style:
note In TypeScript, decorators do not yet affect types.
import {
type Emplaceable,
emplaceable,
} from "https://deno.land/x/upsert/mod.ts";
import { assert } from "https://deno.land/std/testing/asserts.ts";
@emplaceable
class MyMap<K, V> extends Map<K, V> {}
interface MyMap<K, V> extends Emplaceable<K, V> {}
assert(MyMap.prototype.emplace);
EmplaceableMap
Map
with Emplaceable implementation.
import { EmplaceableMap } from "https://deno.land/x/upsert/mod.ts";
import {
assert,
assertInstanceOf,
} from "https://deno.land/std/testing/asserts.ts";
const map = new EmplaceableMap<string, number>();
assertInstanceOf(map, Map);
assert(map.emplace);
EmplaceableWeakMap
WeakMap
with Emplaceable implementation.
import { EmplaceableWeakMap } from "https://deno.land/x/upsert/mod.ts";
import {
assert,
assertInstanceOf,
} from "https://deno.land/std/testing/asserts.ts";
const weakMap = new EmplaceableWeakMap();
assertInstanceOf(weakMap, WeakMap);
assert(weakMap.emplace);
Polyfill
Polyfill affects the global object. You must be very careful when using it.
import "https://deno.land/x/upsert/polyfill.ts";
import { assert } from "https://deno.land/std/testing/asserts.ts";
assert(Map.prototype.emplace);
assert(WeakMap.prototype.emplace);
API
See deno doc for all APIs.
Contributing
See contributing.
License
MIT © 2023 Tomoki Miyauchi