Implemented equal.

README.md

@@ -17,9 +17,10 @@ That is why `ranges-set` operates on actual _ranges_, resulting in performance s
 ## Usage
 
 ```ts
-import { difference, expand, intersection, normalize, subset, union } from 'ranges-set';
+import { difference, equal, expand, intersection, normalize, subset, union } from 'ranges-set';
 
 difference('1-4', '2-3'); // '1,4'
+equal('1-3', '1-2'); // false
 expand('1-3,5-7'); // ['1', '2', '3', '5', '6', '7']
 intersection('1-10', '5-10'); // '5-10'
 normalize('1,2,3,5,6-8'); // '1-3,5-8'
@@ -31,6 +32,7 @@ union('1-60,40-100'); // '1-100'
 
 ```ts
 function difference(textA: string, textB: string): string;
+function equal(textA: string, textB: string): boolean;
 function expand(text: string): string[];
 function intersection(textA: string, textB: string): string;
 function normalize(text: string): string;

index.ts

@@ -8,6 +8,26 @@ type ReprRange = { kind: typeof KindRange; min: number; max: number };
 const numberPattern = /^\s*(?:0|[1-9]\d*)\s*$/;
 const rangePattern = /^\s*(0|[1-9]\d*)\s*-\s*(0|[1-9]\d*)\s*$/;
 
+function compare(reprA: Repr, reprB: Repr): number {
+  if (reprA.kind !== reprB.kind) {
+    return reprA.kind - reprB.kind;
+  }
+
+  switch (reprA.kind) {
+    case KindLiteral:
+      return reprA.text >= (reprB as ReprLiteral).text
+        ? reprA.text > (reprB as ReprLiteral).text
+          ? 1
+          : 0
+        : -1;
+    case KindRange:
+      return (
+        reprA.min - (reprB as ReprRange).min ||
+        reprA.max - (reprB as ReprRange).max
+      );
+  }
+}
+
 export function difference(textA: string, textB: string): string {
   const reprsA = parse(textA);
   const reprsB = parse(textB);
@@ -75,6 +95,26 @@ function differenceReprs(reprsA: Repr[], reprsB: Repr[]): Repr[] {
   return reprs;
 }
 
+export function equal(textA: string, textB: string): boolean {
+  const reprsA = parse(textA);
+  const reprsB = parse(textB);
+  return equalReprs(reprsA, reprsB);
+}
+
+function equalReprs(reprsA: Repr[], reprsB: Repr[]): boolean {
+  if (reprsA.length !== reprsB.length) {
+    return false;
+  }
+
+  for (let index = 0; index < reprsA.length; ++index) {
+    if (compare(reprsA[index], reprsB[index]) !== 0) {
+      return false;
+    }
+  }
+
+  return true;
+}
+
 export function expand(text: string): string[] {
   const reprs = parse(text);
   return expandReprs(reprs);
@@ -144,22 +184,6 @@ export function normalize(text: string): string {
   return serialize(reprs);
 }
 
-function order(reprA: Repr, reprB: Repr): number {
-  if (reprA.kind !== reprB.kind) {
-    return reprA.kind - reprB.kind;
-  }
-
-  switch (reprA.kind) {
-    case KindLiteral:
-      return reprA.text < (reprB as ReprLiteral).text ? -1 : 1;
-    case KindRange:
-      return (
-        reprA.min - (reprB as ReprRange).min ||
-        reprA.max - (reprB as ReprRange).max
-      );
-  }
-}
-
 function parse(text: string): Repr[] {
   return unionReprs(text.split(',').filter(Boolean).map(parseOne));
 }
@@ -269,5 +293,5 @@ function unionReprReducer(reprs: Repr[], repr: Repr): Repr[] {
 }
 
 function unionReprs(reprs: Repr[]): Repr[] {
-  return reprs.sort(order).reduce(unionReprReducer, []);
+  return reprs.sort(compare).reduce(unionReprReducer, []);
 }

test.ts

@@ -1,6 +1,14 @@
 import test from 'ava';
 
-import { difference, expand, intersection, normalize, subset, union } from '.';
+import {
+  difference,
+  equal,
+  expand,
+  intersection,
+  normalize,
+  subset,
+  union,
+} from '.';
 
 function test1<A, B>(fn: (a: A) => B, tests: [A, B][]) {
   for (const [a, b] of tests) {
@@ -50,6 +58,39 @@ test2(difference, [
   ['b,2', 'a,1', 'b,2'],
 ]);
 
+test2(equal, [
+  ['1', '1', true],
+  ['1', '1-2', false],
+  ['1', '2', false],
+  ['1', '2-100', false],
+  ['1', '3', false],
+  ['1,5', '1-5', false],
+  ['1-2', '1', false],
+  ['1-2', '1-2', true],
+  ['1-2', '2', false],
+  ['1-2,3,4-5', '1-5', true],
+  ['1-2,4-5', '1-5', false],
+  ['1-3', '2-4', false],
+  ['1-5', '1,5', false],
+  ['1-5', '1-2,4-5', false],
+  ['1-6', '1,3,6', false],
+  ['1-6', '1,4', false],
+  ['1-6', '1,6', false],
+  ['1-6', '2,4', false],
+  ['1-6', '2-5', false],
+  ['2', '1', false],
+  ['2-100', '1', false],
+  ['2-4', '1-3', false],
+  ['3', '1', false],
+  ['a', 'a', true],
+  ['a', 'b', false],
+  ['a,1', 'b,1', false],
+  ['a,1', 'b,2', false],
+  ['b', 'a', false],
+  ['b,1', 'a,1', false],
+  ['b,2', 'a,1', false],
+]);
+
 test1(expand, [
   [',', []],
   [',,', []],