Add .asEpoch() and .asRandom() (rename .toDate() to .asDate())

ReadMe.md

@@ -19,6 +19,33 @@ A `yid` is:
 * starts off with `Date.now()`
 * uses a substring of https://www.npmjs.com/package/math-random for the second part
 
+## `yid.asDate(id)` ##
+
+Returns the numbers from the first part of the `id` as a `Date()`.
+
+```js
+yid.asDate(id)
+// -> Date: "2018-01-27T10:46:29.798Z"
+```
+
+## `yid.asEpoch(id)` ##
+
+Returns the numbers from the first part of the `id` as a `Number()`.
+
+```js
+yid.asEpoch(id)
+// -> Number: 1517049989798
+```
+
+## `yid.asRandom(id)` ##
+
+Returns the random collection of digits from the second part of the `id`.
+
+```js
+yid.asRandom(id)
+// -> "7496988299172"
+```
+
 ## Why? ##
 
 Why another ID generating library?

index.js

@@ -10,14 +10,31 @@ function yid() {
   return id
 }
 
-function toDate(id) {
+function asDate(id) {
   if ( !id.match(/^\d{13}-\d{13}$/) ) {
-    throw new Error(`Format of id is incorrect: ${id}`)
+    throw new Error(`yid.asDate(): Format of id is incorrect: ${id}`)
   }
   const epoch = id.split('-')[0]
   return new Date(Number(epoch))
 }
 
-yid.toDate = toDate
+function asEpoch(id) {
+  if ( !id.match(/^\d{13}-\d{13}$/) ) {
+    throw new Error(`yid.asEpoch(): Format of id is incorrect: ${id}`)
+  }
+  const epoch = id.split('-')[0]
+  return Number(epoch)
+}
+
+function asRandom(id) {
+  if ( !id.match(/^\d{13}-\d{13}$/) ) {
+    throw new Error(`yid.asRandom(): Format of id is incorrect: ${id}`)
+  }
+  return id.split('-')[1]
+}
+
+yid.asDate = asDate
+yid.asEpoch = asEpoch
+yid.asRandom = asRandom
 
 module.exports = yid

test.js

@@ -1,7 +1,7 @@
 const yid = require('.')
 
 // setup
-const times = 1000000
+const times = 100000
 const count = {
   '22' : 0,
   '23' : 0,
@@ -29,17 +29,26 @@ for(let i = 0; i < times; i++) {
   id = yid()
   count['' + id.length]++
 
-  // check we can get the date back
-  const d = yid.toDate(id)
+  // .asDate()
+  const d = yid.asDate(id)
   if (!(d instanceof Date)) {
-    throw new Error("toDate() returned something that wasn't a date!")
+    throw new Error("asDate() returned something that wasn't a date!")
   }
   if (String(d.valueOf()) != id.split('-')[0]) {
     throw new Error("the date's epoch (d.valueOf()) didn't match the epoch of the id")
   }
-}
 
-console.log('count:', count)
+  // .asEpoch()
+  const epoch = yid.asEpoch(id)
+  if (d.valueOf() != epoch) {
+    throw new Error("the date's epoch didn't match the epoch of the id")
+  }
+
+  // .asRandom()
+  if (yid.asRandom(id) != id.split('-')[1]) {
+    throw new Error("the date's random part didn't match the that of the id")
+  }
+}
 
 if ( count['27'] !== times ) {
   throw new Error("A yid was returned that wasn't 27 chars long")