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@std/collections
Overview Jump to heading
Pure functions for common tasks around collection types like arrays and objects.
Inspired by Kotlin's Collections package and Lodash.
import { intersect, sample, pick } from "@std/collections";
import { assertEquals, assertArrayIncludes } from "@std/assert";
const lisaInterests = ["Cooking", "Music", "Hiking"];
const kimInterests = ["Music", "Tennis", "Cooking"];
assertEquals(intersect(lisaInterests, kimInterests), ["Cooking", "Music"]);
assertArrayIncludes(lisaInterests, [sample(lisaInterests)]);
const cat = { name: "Lulu", age: 3, breed: "Ragdoll" };
assertEquals(pick(cat, ["name", "breed"]), { name: "Lulu", breed: "Ragdoll"});
Add to your project Jump to heading
deno add jsr:@std/collections
See all symbols in @std/collections on
什么是集合类型？ Jump to heading
集合类型是包含多个值的数据结构，如数组和对象。它们允许你将相关数据分组在一起，并对它们执行操作，比如过滤、转换和聚合。
该包提供了一些小型且专注的函数，用于操作这些类型，使你能从简单的构建块组合成复杂操作。
为什么使用 @std/collections？ Jump to heading
collections 包提供了一些小型且纯净的辅助函数（intersect、pick、groupBy、partition），可以替代引入大型工具库。
示例 Jump to heading
distinct 和 distinctBy Jump to heading
import { distinct, distinctBy } from "@std/collections";
const tags = ["a", "b", "a", "c"];
console.log(distinct(tags)); // ["a", "b", "c"]
const people = [
{ id: 1, name: "Alice" },
{ id: 1, name: "Alice v2" },
{ id: 2, name: "Bob" },
];
console.log(distinctBy(people, (p) => p.id));
// [{ id: 1, name: "Alice" }, { id: 2, name: "Bob" }]
映射记录：mapValues, mapKeys Jump to heading
import { mapKeys, mapValues } from "@std/collections";
const rec = { a: 1, b: 2 };
console.log(mapValues(rec, (v) => v * 2)); // { a: 2, b: 4 }
console.log(mapKeys(rec, (k) => k.toUpperCase())); // { A: 1, B: 2 }
深度合并嵌套对象 Jump to heading
import { deepMerge } from "@std/collections/deep-merge";
const a = { cfg: { retries: 2, mode: "fast" } };
const b = { cfg: { retries: 3 } };
console.log(deepMerge(a, b));
// { cfg: { retries: 3, mode: "fast" } }
滑动窗口（带选项） Jump to heading
import { slidingWindows } from "@std/collections";
console.log(slidingWindows([1, 2, 3, 4], 3));
// [[1,2,3],[2,3,4]]
console.log(slidingWindows([1, 2, 3, 4, 5], 3, { step: 2, partial: true }));
// [[1,2,3],[3,4,5],[5]]
按派生键排序 Jump to heading
import { sortBy } from "@std/collections";
const items = [{ v: 2 }, { v: 5 }, { v: 1 }];
console.log(sortBy(items, (i) => i.v));
// [{ v: 1 }, { v: 2 }, { v: 5 }]
console.log(sortBy(items, (i) => i.v, { order: "desc" }));
// [{ v: 5 }, { v: 2 }, { v: 1 }]
分割对象条目 Jump to heading
import { partitionEntries } from "@std/collections";
const user = { id: 1, name: "Sam", active: true, score: 42 };
const [numbers, rest] = partitionEntries(
user,
([, v]) => typeof v === "number",
);
// numbers: { id: 1, score: 42 }
// rest: { name: "Sam", active: true }
生成连接字符串 Jump to heading
import { joinToString } from "@std/collections";
console.log(
joinToString([1, 2, 3], { prefix: "[", separator: ", ", suffix: "]" }),
);
// "[1, 2, 3]"
使用小贴士 Jump to heading
- 函数均为纯函数且以数据优先；不会修改你的输入。
- 优先使用这些基本函数，以保持依赖轻量和代码清晰。