formatter.js

import t from 'should-type';

function looksLikeANumber(n) {
  return !!n.match(/\d+/);
}

function keyCompare(a, b) {
  var aNum = looksLikeANumber(a);
  var bNum = looksLikeANumber(b);
  if (aNum && bNum) {
    return 1*a - 1*b;
  } else if (aNum && !bNum) {
    return -1;
  } else if (!aNum && bNum) {
    return 1;
  } else {
    return a.localeCompare(b);
  }
}

function genKeysFunc(f) {
  return function(value) {
    var k = f(value);
    k.sort(keyCompare);
    return k;
  };
}

export function Formatter(opts) {
  opts = opts || {};

  this.seen = [];

  var keysFunc;
  if (typeof opts.keysFunc === 'function') {
    keysFunc = opts.keysFunc;
  } else if (opts.keys === false) {
    keysFunc = Object.getOwnPropertyNames;
  } else {
    keysFunc = Object.keys;
  }

  this.getKeys = genKeysFunc(keysFunc);

  this.maxLineLength = typeof opts.maxLineLength === 'number' ? opts.maxLineLength : 60;
  this.propSep = opts.propSep || ',';

  this.isUTCdate = !!opts.isUTCdate;
}



Formatter.prototype = {
  constructor: Formatter,

  format: function(value) {
    var tp = t(value);

    if (this.alreadySeen(value)) {
      return '[Circular]';
    }

    var tries = tp.toTryTypes();
    var f = this.defaultFormat;
    while (tries.length) {
      var toTry = tries.shift();
      var name = Formatter.formatterFunctionName(toTry);
      if (this[name]) {
        f = this[name];
        break;
      }
    }
    return f.call(this, value).trim();
  },

  defaultFormat: function(obj) {
    return String(obj);
  },

  alreadySeen: function(value) {
    return this.seen.indexOf(value) >= 0;
  }

};

Formatter.addType = function addType(tp, f) {
  Formatter.prototype[Formatter.formatterFunctionName(tp)] = f;
};

Formatter.formatterFunctionName = function formatterFunctionName(tp) {
  return '_format_' + tp.toString('_');
};