不要怂,就是干,撸起袖子干!

parameter-validator.js 2.5 KB
'use strict';

var cJSON = require('circular-json')
  , _ = require('lodash'); // Don't require Utils here, as it creates a circular dependency

var extractClassName = function(o) {
  if (typeof o === 'string') {
    return o;
  } else if (!!o) {
    return o.toString().match(/function ([^\(]+)/)[1];
  } else {
    return 'undefined';
  }
};

var generateDeprecationWarning = function(value, expectation, options) {
  options = options || {};

  if (options.method && options.index) {
    return [
      'The',
      {1: 'first', 2: 'second', 3: 'third', 4: 'fourth', 5: 'fifth'}[options.index],
      'parameter of',
      options.method,
      'should be a',
      extractClassName(expectation) + '!'
    ].join(' ');
  } else {
    return ['Expected', cJSON.stringify(value), 'to be', extractClassName(expectation) + '!'].join(' ');
  }
};

var matchesExpectation = function(value, expectation) {
  if (typeof expectation === 'string') {
    return (typeof value === expectation.toString());
  } else {
    return (value instanceof expectation);
  }
};

var validateDeprication = function(value, expectation, options) {
  if (options.deprecated) {
    if (matchesExpectation(value, options.deprecated)) {
      options.onDeprecated(options.deprecationWarning);
      return true;
    }
  }
};

var validate = function(value, expectation, options) {
  var result = matchesExpectation(value, expectation);

  if (result) {
    return result;
  } else if (!options.throwError) {
    return false;
  } else {
    var _value = (value === null) ? 'null' : value.toString()
      , _expectation = extractClassName(expectation);

    throw new Error('The parameter (value: ' + _value + ') is no ' + _expectation + '.');
  }
};

var ParameterValidator = module.exports = {
  check: function(value, expectation, options) {
    options = _.extend({
      throwError: true,
      deprecated: false,
      deprecationWarning: generateDeprecationWarning(value, expectation, options),
      onDeprecated: function(s) { console.log('DEPRECATION WARNING:', s); },
      index: null,
      method: null,
      optional: false
    }, options || {});

    if (options.optional && ((value === undefined) || (value === null))) {
      return true;
    }

    if (value === undefined) {
      throw new Error('No value has been passed.');
    }

    if (expectation === undefined) {
      throw new Error('No expectation has been passed.');
    }

    return false
      || validateDeprication(value, expectation, options)
      || validate(value, expectation, options);
  }
};