node/test/parallel/test-stream-transform-hwm0.js

29 lines
692 B
JavaScript

'use strict';
const common = require('../common');
const assert = require('assert');
const { Transform } = require('stream');
const t = new Transform({
objectMode: true, highWaterMark: 0,
transform(chunk, enc, callback) {
process.nextTick(() => callback(null, chunk, enc));
}
});
assert.strictEqual(t.write(1), false);
t.on('drain', common.mustCall(() => {
assert.strictEqual(t.write(2), false);
t.end();
}));
t.once('readable', common.mustCall(() => {
assert.strictEqual(t.read(), 1);
setImmediate(common.mustCall(() => {
assert.strictEqual(t.read(), null);
t.once('readable', common.mustCall(() => {
assert.strictEqual(t.read(), 2);
}));
}));
}));