strom/tests/map.spec.ts
2019-12-02 16:05:27 -05:00

58 lines
1.4 KiB
TypeScript

import { Readable } from "stream";
import test from "ava";
import { expect } from "chai";
import mhysa from "../src";
const { map } = mhysa();
test.cb("map() maps elements synchronously", t => {
t.plan(3);
const source = new Readable({ objectMode: true });
const mapStream = map((element: string) => element.toUpperCase(), {
objectMode: true,
});
const expectedElements = ["A", "B", "C"];
let i = 0;
source
.pipe(mapStream)
.on("data", (element: string) => {
expect(element).to.equal(expectedElements[i]);
t.pass();
i++;
})
.on("error", t.end)
.on("end", t.end);
source.push("a");
source.push("b");
source.push("c");
source.push(null);
});
test.cb("map() maps elements asynchronously", t => {
t.plan(3);
const source = new Readable({ objectMode: true });
const mapStream = map(
async (element: string) => {
await Promise.resolve();
return element.toUpperCase();
},
{ objectMode: true },
);
const expectedElements = ["A", "B", "C"];
let i = 0;
source
.pipe(mapStream)
.on("data", (element: string) => {
expect(element).to.equal(expectedElements[i]);
t.pass();
i++;
})
.on("error", t.end)
.on("end", t.end);
source.push("a");
source.push("b");
source.push("c");
source.push(null);
});