Merge pull request #3987 from MetaMask/dm-docs-1

Documentation for various controllers and and lib utils

4 files changed, 75 insertions, 0 deletions

diff --git a/app/scripts/lib/buy-eth-url.js b/app/scripts/lib/buy-eth-url.js
index b9dde3c28..4e2d0bc79 100644
--- a/app/scripts/lib/buy-eth-url.js
+++ b/app/scripts/lib/buy-eth-url.js
@@ -1,5 +1,16 @@
 module.exports = getBuyEthUrl
 
+/**
+ * Gives the caller a url at which the user can acquire eth, depending on the network they are in
+ *
+ * @param {object} opts Options required to determine the correct url
+ * @param {string} opts.network The network for which to return a url
+ * @param {string} opts.amount The amount of ETH to buy on coinbase. Only relevant if network === '1'.
+ * @param {string} opts.address The address the bought ETH should be sent to.  Only relevant if network === '1'.
+ * @returns {string|undefined} The url at which the user can access ETH, while in the given network. If the passed
+ * network does not match any of the specified cases, or if no network is given, returns undefined.
+ *
+ */
 function getBuyEthUrl ({ network, amount, address }) {
   let url
   switch (network) {
diff --git a/app/scripts/lib/get-first-preferred-lang-code.js b/app/scripts/lib/get-first-preferred-lang-code.js
index e3635434e..5473fccf0 100644
--- a/app/scripts/lib/get-first-preferred-lang-code.js
+++ b/app/scripts/lib/get-first-preferred-lang-code.js
@@ -4,6 +4,13 @@ const allLocales = require('../../_locales/index.json')
 
 const existingLocaleCodes = allLocales.map(locale => locale.code.toLowerCase().replace('_', '-'))
 
+/**
+ * Returns a preferred language code, based on settings within the user's browser. If we have no translations for the
+ * users preferred locales, 'en' is returned.
+ *
+ * @returns {Promise<string>} Promises a locale code, either one from the user's preferred list that we have a translation for, or 'en'
+ *
+ */
 async function getFirstPreferredLangCode () {
   const userPreferredLocaleCodes = await promisify(
     extension.i18n.getAcceptLanguages,
diff --git a/app/scripts/lib/nodeify.js b/app/scripts/lib/nodeify.js
index 9b595d93c..25be6537b 100644
--- a/app/scripts/lib/nodeify.js
+++ b/app/scripts/lib/nodeify.js
@@ -1,6 +1,14 @@
 const promiseToCallback = require('promise-to-callback')
 const noop = function () {}
 
+/**
+ * A generator that returns a function which, when passed a promise, can treat that promise as a node style callback.
+ * The prime advantage being that callbacks are better for error handling.
+ *
+ * @param {Function} fn The function to handle as a callback
+ * @param {Object} context The context in which the fn is to be called, most often a this reference
+ *
+ */
 module.exports = function nodeify (fn, context) {
   return function () {
     const args = [].slice.call(arguments)
diff --git a/app/scripts/lib/util.js b/app/scripts/lib/util.js
index df815906f..431d1e59c 100644
--- a/app/scripts/lib/util.js
+++ b/app/scripts/lib/util.js
@@ -7,11 +7,26 @@ const {
   ENVIRONMENT_TYPE_FULLSCREEN,
 } = require('./enums')
 
+/**
+ * Generates an example stack trace
+ *
+ * @returns {string} A stack trace
+ *
+ */
 function getStack () {
   const stack = new Error('Stack trace generator - not an error').stack
   return stack
 }
 
+/**
+ * Used to determine the window type through which the app is being viewed.
+ *  - 'popup' refers to the extension opened through the browser app icon (in top right corner in chrome and firefox)
+ *  - 'responsive' refers to the main browser window
+ *  - 'notification' refers to the popup that appears in its own window when taking action outside of metamask
+ *
+ * @returns {string} A single word label that represents the type of window through which the app is being viewed
+ *
+ */
 const getEnvironmentType = (url = window.location.href) => {
   if (url.match(/popup.html(?:\?.+)*$/)) {
     return ENVIRONMENT_TYPE_POPUP
@@ -22,6 +37,17 @@ const getEnvironmentType = (url = window.location.href) => {
   }
 }
 
+/**
+ * Checks whether a given balance of ETH, represented as a hex string, is sufficient to pay a value plus a gas fee
+ *
+ * @param {object} txParams Contains data about a transaction
+ * @param {string} txParams.gas The gas for a transaction
+ * @param {string} txParams.gasPrice The price per gas for the transaction
+ * @param {string} txParams.value The value of ETH to send
+ * @param {string} hexBalance A balance of ETH represented as a hex string
+ * @returns {boolean} Whether the balance is greater than or equal to the value plus the value of gas times gasPrice
+ *
+ */
 function sufficientBalance (txParams, hexBalance) {
   // validate hexBalance is a hex string
   assert.equal(typeof hexBalance, 'string', 'sufficientBalance - hexBalance is not a hex string')
@@ -36,14 +62,37 @@ function sufficientBalance (txParams, hexBalance) {
   return balance.gte(maxCost)
 }
 
+/**
+ * Converts a BN object to a hex string with a '0x' prefix
+ *
+ * @param {BN} inputBn The BN to convert to a hex string
+ * @returns {string} A '0x' prefixed hex string
+ *
+ */
 function bnToHex (inputBn) {
   return ethUtil.addHexPrefix(inputBn.toString(16))
 }
 
+/**
+ * Converts a hex string to a BN object
+ *
+ * @param {string} inputHex A number represented as a hex string
+ * @returns {Object} A BN object
+ *
+ */
 function hexToBn (inputHex) {
   return new BN(ethUtil.stripHexPrefix(inputHex), 16)
 }
 
+/**
+ * Used to multiply a BN by a fraction
+ *
+ * @param {BN} targetBN The number to multiply by a fraction
+ * @param {number|string} numerator The numerator of the fraction multiplier
+ * @param {number|string} denominator The denominator of the fraction multiplier
+ * @returns {BN} The product of the multiplication
+ *
+ */
 function BnMultiplyByFraction (targetBN, numerator, denominator) {
   const numBN = new BN(numerator)
   const denomBN = new BN(denominator)