codekingpro/portable-devtools

1// The tracker class is intentionally as naive as possible.  it is just
2// an ergonomic wrapper around process.emit('progress', ...)
3const EE = require('events')
4class Tracker extends EE {
5  constructor (name, key, total) {
6    super()
7    if (!name) {
8      throw new Error('proggy: Tracker needs a name')
9    }
10
11    if (typeof key === 'number' && !total) {
12      total = key
13      key = null
14    }
15
16    if (!total) {
17      total = 100
18    }
19
20    if (!key) {
21      key = name
22    }
23
24    this.done = false
25    this.name = name
26    this.key = key
27    this.value = 0
28    this.total = total
29  }
30
31  finish (metadata = {}) {
32    this.update(this.total, this.total, metadata)
33  }
34
35  update (value, total, metadata) {
36    if (!metadata) {
37      if (total && typeof total === 'object') {
38        metadata = total
39      } else {
40        metadata = {}
41      }
42    }
43    if (typeof total !== 'number') {
44      total = this.total
45    }
46
47    if (this.done) {
48      const msg = `proggy: updating completed tracker: ${JSON.stringify(this.key)}`
49      throw new Error(msg)
50    }
51    this.value = value
52    this.total = total
53    const done = this.value >= this.total
54    process.emit('progress', this.key, {
55      ...metadata,
56      name: this.name,
57      key: this.key,
58      value,
59      total,
60      done,
61    })
62    if (done) {
63      this.done = true
64      this.emit('done')
65    }
66  }
67}
68module.exports = Tracker
69