node/test/common/countdown.js

29 lines
590 B
JavaScript

'use strict';
const assert = require('assert');
const kLimit = Symbol('limit');
const kCallback = Symbol('callback');
const common = require('./');
class Countdown {
constructor(limit, cb) {
assert.strictEqual(typeof limit, 'number');
assert.strictEqual(typeof cb, 'function');
this[kLimit] = limit;
this[kCallback] = common.mustCall(cb);
}
dec() {
assert(this[kLimit] > 0, 'Countdown expired');
if (--this[kLimit] === 0)
this[kCallback]();
return this[kLimit];
}
get remaining() {
return this[kLimit];
}
}
module.exports = Countdown;