size-range/index.js at main · cedrictailly/size-range · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132

const units = {};

units.byte      = {text: "b",  value: 1};
units.kilobyte  = {text: "kb", value: units.byte.value * 1024};
units.megabyte  = {text: "mb", value: units.kilobyte.value * 1024};
units.gigabyte  = {text: "gb", value: units.megabyte.value * 1024};
units.terabyte  = {text: "tb", value: units.gigabyte.value * 1024};
units.petabyte  = {text: "pb", value: units.terabyte.value * 1024};
units.exabyte   = {text: "eb", value: units.petabyte.value * 1024};
units.zettabyte = {text: "zb", value: units.exabyte.value * 1024};
units.yottabyte = {text: "yb", value: units.zettabyte.value * 1024};

const regexes = {};

regexes.range      = /^(?<min>.+?)-(?<max>.+?)$/i;
regexes.between    = /^between\s+(?<min>.+?)\s+and\s+(?<max>.+?)$/i;
regexes.comparison = /^(?<operator>\b(?:min|max|equal)\b|=|<=?|>=?)?\s*(?<value>.+?)$/i;

function parseSize(text) {

  const match = text.toString().trim().match(/^(?<value>[\d.]+)\s*(?<unit>.+?)?$/);

  if (!match)
    return null;

  const value = parseFloat(match.groups.value);

  if (isNaN(value))
    return null;

  match.groups.unit = (match.groups.unit || "b").toLowerCase();

  const unit = Object.values(units).find(item => item.text === match.groups.unit);

  if (!unit)
    return null;

  return value * unit.value;
}

function parseRange(text) {

  text = text.toString().trim();

  for (const regex of Object.values(regexes)) {

    const match = text.match(regex);

    if (!match)
      continue;

    let result = {...match.groups};

    for (const name of ["min", "max", "value"]) {

      if (! result[name])
        continue;

      result[name] = exports.parseSize(result[name]);

      if (result[name] === null)
        return null;
    }

    if (result.value !== undefined) {
      if (result.operator === undefined)
        result.operator = "=";
      else if (result.operator === "min")
        result.operator = ">=";
      else if (result.operator === "max")
        result.operator = "<=";
    } else {
      result = {
        min: Math.min(result.min, result.max),
        max: Math.max(result.min, result.max),
      };
    }

    return result;
  }

  return null;
}

class SizeRange {

  constructor(text) {

    this.config = parseRange(text);

    if (!this.config)
      throw new Error(`Invalid range: ${text}`);
  }

  check(size) {

    if (this.config.value !== undefined) {
      switch (this.config.operator) {
      case "=":  return size == this.config.value;
      case ">":  return size >  this.config.value;
      case ">=": return size >= this.config.value;
      case "<":  return size <  this.config.value;
      case "<=": return size <= this.config.value;
      default:
        throw new Error(`Invalid operator: ${this.config.operator}`);
      }
    }

    return size >= this.config.min && size <= this.config.max;
  }

  async checkFile(file) {
    return this.check(
      (await require("fs").promises.stat(file)).size,
    );
  }

  checkFileSync(file) {
    return this.check(
      require("fs").statSync(file).size,
    );
  }
}

exports.units      = units;
exports.regexes    = regexes;
exports.parseSize  = parseSize;
exports.parseRange = parseRange;
exports.SizeRange  = SizeRange;

module.exports = text => new SizeRange(text);