selectGasPrice.js

/**
Template Controllers

@module Templates
*/

/**
The select gas price template

@class [template] dapp_selectGasPrice
@constructor
*/

/**
The the factor by which the gas price should be changeable.

@property toPowerFactor
*/
var toPowerFactor = 2;

/**
Calculates the gas * gas price.

@method calculateGasInWei
@return {Number}
*/
var calculateGasInWei = function(template, gas, gasPrice, returnGasPrice) {
  // Only defaults to 20 shannon if there's no default set
  gasPrice = gasPrice || 20000000000;

  if (!_.isObject(gasPrice)) gasPrice = new BigNumber(String(gasPrice), 10);

  if (_.isUndefined(gas)) {
    console.warn("No gas provided for {{> dapp_selectGasPrice}}");
    return new BigNumber(0);
  }

  var feeMultiplicator = Number(TemplateVar.get(template, "feeMultiplicator"));

  // divide and multiply to round it to the nearest billion wei (1 shannon)
  var billion = new BigNumber(1000000000);
  gasPrice = gasPrice
    .times(new BigNumber(toPowerFactor).toPower(feeMultiplicator))
    .dividedBy(billion)
    .round()
    .times(billion);

  return returnGasPrice ? gasPrice : gasPrice.times(gas);
};

Template["dapp_selectGasPrice"].onCreated(function() {
  TemplateVar.set("gasInWei", "0");
  TemplateVar.set("gasPrice", "0");
  TemplateVar.set("feeMultiplicator", 0);
});

Template["dapp_selectGasPrice"].helpers({
  /**
    Return the currently selected fee value calculate with gas price

    @method (fee)
    */
  fee: function() {
    if (
      _.isFinite(TemplateVar.get("feeMultiplicator")) &&
      _.isFinite(this.gas)
    ) {
      var template = Template.instance();

      // set the value
      TemplateVar.set(
        "gasInWei",
        calculateGasInWei(template, this.gas, this.gasPrice)
          .floor()
          .toString(10)
      );
      TemplateVar.set(
        "gasPrice",
        calculateGasInWei(template, this.gas, this.gasPrice, true)
          .floor()
          .toString(10)
      );

      // return the fee
      return EthTools.formatBalance(
        calculateGasInWei(template, this.gas, this.gasPrice).toString(10),
        "0,0.[000000000000000000] UNIT",
        "ether"
      );
    }
  },
  /**
    Return the current unit

    @method (unit)
    */
  unit: function() {
    var unit = this.unit || EthTools.getUnit();
    if (unit) return unit.toUpperCase();
  },
  /**
    Get the correct text, if TAPi18n is available.

    @method i18nText
    */
  i18nText: function(key) {
    if (
      typeof TAPi18n !== "undefined" &&
      TAPi18n.__("elements.selectGasPrice." + key) !==
        "elements.selectGasPrice." + key
    ) {
      return TAPi18n.__("elements.selectGasPrice." + key);
    } else if (typeof this[key] !== "undefined") {
      return this[key];
    } else {
      return key === "high" ? "+" : "-";
    }
  }
});

Template["dapp_selectGasPrice"].events({
  /**
    Change the selected fee
    
    @event change input[name="fee"], input input[name="fee"]
    */
  'change input[name="fee"], input input[name="fee"]': function(e) {
    TemplateVar.set("feeMultiplicator", Number(e.currentTarget.value));
  }
});