Performance improvements

It stringifies slower than v1 and JSON, but it parses faster than v1 and JSON :)

examples/performance.html

@@ -5,6 +5,23 @@
 <script>
 	const count = 200000
 	const v = { a: [ [1, 2], [], false, {}, true ], b: [], c: { d: 'hello', e: {}, f: [], g: true, n: null } }
+	const JSONParse = () => {
+		const n = Date.now()
+		const s = JSON.stringify(v)
+		for (let i = 0; i < count; i++) {
+			JSON.parse(s)
+		}
+		const ms = Date.now() - n
+		console.log(`JSON: ${count} parsed in ${ms}ms, ${ms / count}ms/item`)
+	}
+	const JSONStringify = () => {
+		const n = Date.now()
+		for (let i = 0; i < count; i++) {
+			JSON.stringify(v)
+		}
+		const ms = Date.now() - n
+		console.log(`JSON: ${count} stringified in ${ms}ms, ${ms / count}ms/item`)
+	}
 	const v1Parse = () => {
 		const n = Date.now()
 		const s = JSURL.stringify(v)
@@ -40,6 +57,8 @@
 		console.log(`v2: ${count} stringified in ${ms}ms, ${ms / count}ms/item`)
 	}
 	window.onload = () => {
+		JSONParse()
+		JSONStringify()
 		v1Parse()
 		v1Stringify()
 		v2Parse()

lib/jsurl2.js

@@ -56,11 +56,13 @@
 	}
 	var escapeRE = /(_|\*.)/g
 	function unescape (s) {
-		return s.replace(escapeRE, origChar)
+		// oddly enough, testing first is faster
+		return escapeRE.test(s) ? s.replace(escapeRE, origChar) : s
 	}
 	var replaceRE = /([*_~%$+'() ])/g
 	function escape (s) {
-		return s.replace(replaceRE, escCode)
+		// oddly enough, testing first is faster
+		return replaceRE.test(s) ? s.replace(replaceRE, escCode) : s
 	}
 	function eat (a) {
 		var j, c
@@ -125,20 +127,21 @@
 			} else {
 				throw new Error('Unknown dict reference', k)
 			}
+		} else if (c === '*') {
+			eatOne(a)
+			out = unescape(eat(a))
 		} else if (numRE.test(c)) {
 			out = Number(eat(a))
 		} else if (stringRE.test(c)) {
 			out = unescape(eat(a))
-		} else if (c === '*') {
-			eatOne(a)
-			out = unescape(eat(a))
 		} else {
 			throw new Error('Cannot decode part ' + [t].concat(a).join('~'))
 		}
 		return out
 	}
 
 	var endTildesRE = /~*$/
+	var TRUEt = TRUE + '~'
 	function encode (v) {
 		var t, a, out, T = typeof v, val
 
@@ -161,20 +164,19 @@
 			} else if (Array.isArray(v)) {
 				a = []
 				for (var i = 0; i < v.length; i++) {
-					t = encode(v[i])
+					t = v[i]
 					// Special case: only use full -T~ in arrays
-					a[i] = (t === '~' ? TRUE + '~' : t) || NULL
+					a[i] = t === true ? TRUEt : encode(t)
 				}
 
 				out = '!' + a.join('')
 			} else {
 				a = []
 				for (var key in v) {
 					if (v.hasOwnProperty(key)) {
-						val = encode(v[key])
-
-						// skip undefined and functions
-						if (val !== UNDEF + '~') {
+						t = v[key]
+						if (t !== undefined && typeof t !== 'function') {
+							val = encode(t)
 							a.push(escape(key) + '~', val)
 						}
 					}