Update URL with "permalink" to current value

Use Base 62 for compactness. Note that this requires us to upgrade the
internals to handle bigger bases, even though we don't expose base > 36
elsewhere in the UI.

This fulfils the promise in the README that this feature exists.

diff --git a/src/App.js b/src/App.js
index f6678cf3dca632fdc26d0dbc2c40a45d909bd5ec..b3ff45d9530041ce26be2d449507ca973975449f 100644 (file)
--- a/src/App.js
+++ b/src/App.js
@@ -7,25 +7,48 @@
 
 'use strict';
 
+import DIGITS from './DIGITS';
 import DynamicField from './DynamicField.react';
 import React from 'react';
 import type Value from './Field.react';
 import Field from './Field.react';
 import Label from './Label.react';
 import Size from './Size.react';
+import convert from './convert';
 
 import './App.css';
 
+const SERIALIZATION_BASE = DIGITS.length;
+
+function getInitialValue() {
+  // Extract value from URL fragment, if present.
+  const value = window.location.hash.replace(/^#/, '');
+  const validator = new RegExp(`^[${DIGITS}]+$`);
+  if (!validator.test(value)) {
+    return null;
+  } else {
+    return {
+      base: SERIALIZATION_BASE,
+      value,
+    };
+  }
+}
+
 export default class App extends React.Component {
   constructor(props) {
     super(props);
     this.state = {
-      value: null,
+      value: getInitialValue(),
     };
   }
 
   _onValueChange = (value: Value) => {
     this.setState({value});
+    window.history.replaceState(
+      {},
+      '',
+      '#' + convert(value.value, value.base, SERIALIZATION_BASE)
+    );
   }
 
   componentDidMount() {

diff --git a/src/DIGITS.js b/src/DIGITS.js
new file mode 100644 (file)
index 0000000..8929e89
--- /dev/null
+++ b/src/DIGITS.js
@@ -0,0 +1,12 @@
+/**
+ * Copyright 2015-present Greg Hurrell. All rights reserved.
+ * Licensed under the terms of the MIT license.
+ *
+ * @flow
+ */
+
+'use strict';
+
+const DIGITS = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
+
+export default DIGITS;

diff --git a/src/Field.react.js b/src/Field.react.js
index b5d201003869becd6729b1e840b428b7a93d427d..a2e39a839c610a1a33d8715db70558699131d511 100644 (file)
--- a/src/Field.react.js
+++ b/src/Field.react.js
@@ -7,6 +7,7 @@
 
 'use strict';
 
+import DIGITS from './DIGITS';
 import React from 'react';
 import convert from './convert';
 import cx from 'classnames';
@@ -20,8 +21,6 @@ export const ValuePropType = React.PropTypes.shape({
   value: React.PropTypes.string,
 });
 
-const DIGITS = '0123456789abcdefghijklmnopqrstuvwxyz';
-
 /**
  * Convert from `value` to `base`.
  */

diff --git a/src/getDigits.js b/src/getDigits.js
index fc8888da40fe64c3e8c0f7c202474400c8eac417..fed0aa38439900d23800214978795a6f8d90e7c5 100644 (file)
--- a/src/getDigits.js
+++ b/src/getDigits.js
@@ -7,6 +7,8 @@
 
 'use strict';
 
+import DIGITS from './DIGITS';
+
 /**
  * Strips the leading prefix from `number` in `base` and returns the remaining
  * part of the string.
@@ -26,6 +28,15 @@ function stripPrefix(number: string, base: number): string {
   }
 }
 
+function parse(digit: string, base: number) {
+  if (base > 36 && base <= 62) {
+    const position = DIGITS.indexOf(digit);
+    return position !== -1 && position < base ? position + 1 : NaN;
+  } else {
+    return parseInt(digit, base);
+  }
+}
+
 /**
  * Breaks the string repsentation of `number` in `base` into an array of decimal
  * digits (from least significant to most significant) for easier manipulation.
@@ -35,7 +46,7 @@ function stripPrefix(number: string, base: number): string {
  */
 export default function getDigits(number: string, base: number): Array<number> {
   return stripPrefix(number, base).trim().split('').reverse().map(digit => {
-    const result = parseInt(digit, base);
+    const result = parse(digit, base);
     if (isNaN(result)) {
       throw new Error('Invalid digit `' + digit + '` for base `' + base + '`');
     }

diff --git a/src/joinDigits.js b/src/joinDigits.js
index 3d6eae2f82fa7836697d50c364138c21dfe8e3f6..83d8d975a839f46a51b64a02d50f7736bfc0d765 100644 (file)
--- a/src/joinDigits.js
+++ b/src/joinDigits.js
@@ -7,6 +7,16 @@
 
 'use strict';
 
+import DIGITS from './DIGITS';
+
+function encode(number: string, base: number) {
+  if (base > 36 && base <=62) {
+    return DIGITS[number - 1];
+  } else {
+    return number.toString(base);
+  }
+}
+
 /**
  * Turns an unpacked arbitrary-precision representation of a number, `digits`,
  * (as produced by `getDigits`) back into a string representation in `base`.
@@ -18,6 +28,6 @@ export default function joinDigits(
   return digits
     .slice()
     .reverse()
-    .map(number => number.toString(base))
+    .map(number => encode(number, base))
     .join('');
 }