commands/validation.js

  1. /**
  2.  * Command validation functions and utils.
  3.  * @namespace validation
  4.  * @memberof commands
  5.  */
  7. //////////////////////////////////////////////////////////////////////////////
  8. // Validation function factories
  9. //////////////////////////////////////////////////////////////////////////////
  11. /**
  12.  * A factory for a validation function based on a type.
  13.  * @memberof commands.validation
  14.  * @param {string} type - "Type" of the validation function. Any text that represents this type.
  15.  * @param {string} [base=type] - Base JavaScript type: "string", "number", "boolean", etc.
  16.  * @returns {commands.Validate} Validation function.
  17.  */
  18. const makeType = (type, base = type) => {
  19.   const v = e => typeof e === base; // eslint-disable-line valid-typeof
  20.   v.exp = v.type = type;
  21.   v.base = base;
  22.   return v;
  23. };
  25. /**
  26.  * A factory for a validation function based on a number.
  27.  * @memberof commands.validation
  28.  * @param {string} [type='number'] - "Type" of the validation function. Any text that represents this type.
  29.  * @param {number} [min] - Minimum value.
  30.  * @param {number} [max] - Maximum value.
  31.  * @returns {commands.Validate} Validation function.
  32.  */
  33. const makeNumber = (type = 'number', min = null, max = null) => {
  34.   const hasMin = typeof min === 'number';
  35.   const hasMax = typeof max === 'number';
  36.   const v = n => {
  37.     if (typeof n !== 'number') return false;
  38.     if (hasMin && n < min) return false;
  39.     if (hasMax && n > max) return false;
  40.     return true;
  41.   };
  42.   v.base = 'number';
  43.   v.exp = v.type = type;
  44.   if (hasMin || hasMax) v.exp += ` [${hasMin?min:'-∞'},${hasMax?max:'+∞'}]`;
  45.   if (hasMin) v.min = min;
  46.   if (hasMax) v.max = max;
  47.   return v;
  48. };
  50. /**
  51.  * A factory for a validation function based on a number of string options.
  52.  * @memberof commands.validation
  53.  * @param {string} type - "Type" of the validation function. Any text that represents this type.
  54.  * @param {string[]} options - Options the validation function accepts. Must not be empty.
  55.  * @returns {commands.Validate} Validation function.
  56.  */
  57. const makeOptions = (type, options) => {
  58.   const v = e => options.indexOf(e) >= 0;
  59.   v.base = 'string';
  60.   v.exp = `"${options.join('" or "')}"`;
  61.   v.type = type;
  62.   v.options = options;
  63.   return v;
  64. };
  66. /**
  67.  * A factory for a validation function that combines other validation functions with "and".
  68.  * @memberof commands.validation
  69.  * @package
  70.  * @param {...commands.Validate} vfs - Validation functions to combine.
  71.  * @returns {commands.Validate} Combined validation function.
  72.  */
  73. const and = (...vfs) => {
  74.   vfs = [...new Set(vfs)]; // remove duplicates
  75.   if (vfs.length === 1) return vfs[0];
  76.   const v = e => vfs.every(vf => vf(e));
  77.   v.base = 'object';
  78.   v.exp = vfs.map(vf => vf.exp).join(' and ');
  79.   return v;
  80. };
  82. //////////////////////////////////////////////////////////////////////////////
  83. // Validation functions
  84. //////////////////////////////////////////////////////////////////////////////
  86. /**
  87.  * A validation function for an identifier.
  88.  * @memberof commands.validation
  89.  * @param {string} s - String to test.
  90.  * @returns {boolean} If the input is a valid identifier.
  91.  */
  92. const isIdentifier = s =>
  93.   // A negative look behind to check for a string that does NOT end with a dash
  94.   // is only supported on node 8.9.4 with the --harmony flag
  95.   // https://node.green/#ES2018-features--RegExp-Lookbehind-Assertions
  96.   // /^[a-z_][a-z_0-9-]*(?<!-)$/i
  97.   /^[a-z_][a-z_0-9-]*$/i.test(s) && /[^-]$/.test(s);
  98. isIdentifier.exp = 'identifier';
  100. /**
  101.  * A validation function for a string.
  102.  * @memberof commands.validation
  103.  * @param {object} e - Object to test.
  104.  * @returns {boolean} If the input is of type 'string'.
  105.  */
  106. const isString = makeType('string');
  108. /**
  109.  * A validation function for a command.
  110.  * @memberof commands.validation
  111.  * @param {object} e - Object to test.
  112.  * @returns {boolean} If the input is of type 'function', assumed to be a command function.
  113.  */
  114. const isCommand = makeType('command', 'function');
  116. /**
  117.  * A validation function for a number of milliseconds (mininum value 70).
  118.  * @memberof commands.validation
  119.  * @param {object} e - Object to test.
  120.  * @returns {boolean} If the input is a number of milliseconds.
  121.  */
  122. const isMs = makeNumber('ms', 70); // arbitrary lower limit for milliseconds
  124. /**
  125.  * A validation function for a number of seconds (mininum value 1).
  126.  * @memberof commands.validation
  127.  * @param {object} e - Object to test.
  128.  * @returns {boolean} If the input is a number of seconds.
  129.  */
  130. const isSeconds = makeNumber('second', 1);
  132. /**
  133.  * A validation function for a number of minutes (mininum value 1).
  134.  * @memberof commands.validation
  135.  * @param {object} e - Object to test.
  136.  * @returns {boolean} If the input is a number of minutes.
  137.  */
  138. const isMinutes = makeNumber('minute', 1);
  140. /**
  141.  * A validation function for a number of times (mininum value 1).
  142.  * @memberof commands.validation
  143.  * @param {object} e - Object to test.
  144.  * @returns {boolean} If the input is a number of times.
  145.  */
  146. const isTimes = makeNumber('times', 1);
  148. //////////////////////////////////////////////////////////////////////////////
  150. module.exports = {
  151.   makeType,
  152.   makeNumber,
  153.   makeOptions,
  154.   and,
  155.   isIdentifier,
  156.   isString,
  157.   isCommand,
  158.   isMs,
  159.   isSeconds,
  160.   isMinutes,
  161.   isTimes
  162. };