ts-pattern - npm Package Compare versions

Comparing version 0.1.8 to 0.1.9

lib/index.d.ts

@@ -0,1 +1,2 @@
+import { ValueOf, LeastUpperBound, ExcludeIfContainsNever, UnionToIntersection } from './types/helpers';
 /**
@@ -9,3 +10,4 @@ * # Pattern matching
     Guard = "@match/guard",
-    Not = "@match/not"
+    Not = "@match/not",
+    Select = "@match/select"
 }
@@ -49,2 +51,6 @@ /**
 };
+declare type SelectPattern<k extends string> = {
+    patternKind: PatternType.Select;
+    key: k;
+};
 declare type SpecialPattern<a> = a extends number ? typeof __.number | __ : a extends string ? typeof __.string | __ : a extends boolean ? typeof __.boolean | __ : __;
@@ -56,4 +62,4 @@ /**
  */
-export declare type Pattern<a> = GuardPattern<a> | NotPattern<a | any> | SpecialPattern<a> | (a extends Primitives ? a : a extends [infer b, infer c, infer d, infer e, infer f] ? readonly [Pattern<b>, Pattern<c>, Pattern<d>, Pattern<e>, Pattern<f>] : a extends [infer b, infer c, infer d, infer e] ? readonly [Pattern<b>, Pattern<c>, Pattern<d>, Pattern<e>] : a extends [infer b, infer c, infer d] ? readonly [Pattern<b>, Pattern<c>, Pattern<d>] : a extends [infer b, infer c] ? readonly [Pattern<b>, Pattern<c>] : a extends (infer b)[] ? readonly Pattern<b>[] : a extends Map<infer k, infer v> ? Map<k, Pattern<v>> : a extends Set<infer v> ? Set<Pattern<v>> : a extends object ? {
-    readonly [k in keyof a]?: Pattern<a[k]>;
+export declare type Pattern<a> = SelectPattern<string> | GuardPattern<a> | NotPattern<a | any> | SpecialPattern<a> | (a extends Primitives ? a : a extends [infer b, infer c, infer d, infer e, infer f] ? [Pattern<b>, Pattern<c>, Pattern<d>, Pattern<e>, Pattern<f>] : a extends [infer b, infer c, infer d, infer e] ? [Pattern<b>, Pattern<c>, Pattern<d>, Pattern<e>] : a extends [infer b, infer c, infer d] ? [Pattern<b>, Pattern<c>, Pattern<d>] : a extends [infer b, infer c] ? [Pattern<b>, Pattern<c>] : a extends (infer b)[] ? Pattern<b>[] : a extends Map<infer k, infer v> ? Map<k, Pattern<v>> : a extends Set<infer v> ? Set<Pattern<v>> : a extends object ? {
+    [k in keyof a]?: Pattern<a[k]>;
 } : a);
@@ -65,35 +71,49 @@ /**
  */
-declare type InvertPattern<p> = p extends typeof __.number ? number : p extends typeof __.string ? string : p extends typeof __.boolean ? boolean : p extends __ ? __ : p extends GuardPattern<infer pb> ? GuardValue<p['when']> : p extends NotPattern<infer pb> ? {
+declare type InvertPattern<p> = p extends typeof __.number ? number : p extends typeof __.string ? string : p extends typeof __.boolean ? boolean : p extends SelectPattern<string> ? __ : p extends __ ? __ : p extends GuardPattern<infer pb> ? GuardValue<p['when']> : p extends NotPattern<infer pb> ? {
     valueKind: PatternType.Not;
     value: InvertPattern<pb>;
-} : p extends Primitives ? p : p extends readonly [infer pb, infer pc, infer pd, infer pe, infer pf] ? [InvertPattern<pb>, InvertPattern<pc>, InvertPattern<pd>, InvertPattern<pe>, InvertPattern<pf>] : p extends readonly [infer pb, infer pc, infer pd, infer pe] ? [InvertPattern<pb>, InvertPattern<pc>, InvertPattern<pd>, InvertPattern<pe>] : p extends readonly [infer pb, infer pc, infer pd] ? [InvertPattern<pb>, InvertPattern<pc>, InvertPattern<pd>] : p extends readonly [infer pb, infer pc] ? [InvertPattern<pb>, InvertPattern<pc>] : p extends readonly (infer pp)[] ? InvertPattern<pp>[] : p extends Map<infer pk, infer pv> ? Map<pk, InvertPattern<pv>> : p extends Set<infer pv> ? Set<InvertPattern<pv>> : p extends object ? {
+} : p extends Primitives ? p : p extends [infer pb, infer pc, infer pd, infer pe, infer pf] ? [InvertPattern<pb>, InvertPattern<pc>, InvertPattern<pd>, InvertPattern<pe>, InvertPattern<pf>] : p extends [infer pb, infer pc, infer pd, infer pe] ? [InvertPattern<pb>, InvertPattern<pc>, InvertPattern<pd>, InvertPattern<pe>] : p extends [infer pb, infer pc, infer pd] ? [InvertPattern<pb>, InvertPattern<pc>, InvertPattern<pd>] : p extends [infer pb, infer pc] ? [InvertPattern<pb>, InvertPattern<pc>] : p extends (infer pp)[] ? InvertPattern<pp>[] : p extends Map<infer pk, infer pv> ? Map<pk, InvertPattern<pv>> : p extends Set<infer pv> ? Set<InvertPattern<pv>> : p extends object ? {
     [k in keyof p]: InvertPattern<p[k]>;
 } : p;
-/**
- * ### LeastUpperBound
- * An interesting one. A type taking two imbricated sets and returning the
- * smallest one.
- * We need that because sometimes the pattern's infered type holds more
- * information than the value on which we are matching (if the value is any
- * or unknown for instance).
- */
-declare type LeastUpperBound<a, b> = b extends a ? b : a extends b ? a : never;
 declare type ExtractMostPreciseValue<a, b> = b extends [] ? [] : [a, b] extends [[infer a1, infer a2, infer a3, infer a4, infer a5] | infer otherBranches, [infer b1, infer b2, infer b3, infer b4, infer b5]] ? [ExtractMostPreciseValue<a1, b1>, ExtractMostPreciseValue<a2, b2>, ExtractMostPreciseValue<a3, b3>, ExtractMostPreciseValue<a4, b4>, ExtractMostPreciseValue<a5, b5>] : [a, b] extends [[infer a1, infer a2, infer a3, infer a4] | infer otherBranches, [infer b1, infer b2, infer b3, infer b4]] ? [ExtractMostPreciseValue<a1, b1>, ExtractMostPreciseValue<a2, b2>, ExtractMostPreciseValue<a3, b3>, ExtractMostPreciseValue<a4, b4>] : [a, b] extends [[infer a1, infer a2, infer a3] | infer otherBranches, [infer b1, infer b2, infer b3]] ? [ExtractMostPreciseValue<a1, b1>, ExtractMostPreciseValue<a2, b2>, ExtractMostPreciseValue<a3, b3>] : [a, b] extends [[infer a1, infer a2] | infer otherBranches, [infer b1, infer b2]] ? [ExtractMostPreciseValue<a1, b1>, ExtractMostPreciseValue<a2, b2>] : [a, b] extends [(infer a1)[], (infer b1)[]] ? ExtractMostPreciseValue<a1, b1>[] : [a, b] extends [Map<infer ak, infer av>, Map<infer bk, infer bv>] ? Map<ExtractMostPreciseValue<ak, bk>, ExtractMostPreciseValue<av, bv>> : [a, b] extends [Set<infer av>, Set<infer bv>] ? Set<ExtractMostPreciseValue<av, bv>> : b extends __ ? a : b extends {
     valueKind: PatternType.Not;
     value: infer b1;
-} ? Exclude<a, b1> extends never ? a : Exclude<a, b1> : b extends object ? ObjectExtractMostPreciseValue<a, b> : LeastUpperBound<a, b>;
-/**
- * if a key of an object has the never type,
- * returns never, otherwise returns the type of object
- **/
-declare type ExcludeIfContainsNever<a> = ValueOf<{
-    [k in keyof a]: a[k] extends never ? 'exclude' : 'include';
-}> extends 'include' ? a : never;
+} ? Exclude<a, b1> : b extends object ? ObjectExtractMostPreciseValue<a, b> : LeastUpperBound<a, b>;
 declare type ObjectExtractMostPreciseValue<a, b> = b extends a ? b : a extends b ? a : ExcludeIfContainsNever<{
-    [k in keyof a]-?: k extends keyof b ? ExtractMostPreciseValue<a[k], b[k]> : a[k];
+    [k in keyof Required<a>]: k extends keyof b ? ExtractMostPreciseValue<a[k], b[k]> : a[k];
 }>;
-declare type ValueOf<a> = a[keyof a];
-declare type MatchedValue<a, p extends Pattern<a>> = ExtractMostPreciseValue<a, InvertPattern<p>>;
+declare type MatchedValue<a, p extends Pattern<a>> = ExtractMostPreciseValue<a, InvertPattern<p>> extends never ? a : ExtractMostPreciseValue<a, InvertPattern<p>>;
+declare type FindSelected<a, b> = b extends SelectPattern<infer Key> ? {
+    [k in Key]: a;
+} : [a, b] extends [object, object] ? ValueOf<{
+    [k in keyof a & keyof b]: FindSelected1<a[k], b[k]>;
+}> : never;
+declare type FindSelected1<a, b> = b extends SelectPattern<infer Key> ? {
+    [k in Key]: a;
+} : [a, b] extends [object, object] ? ValueOf<{
+    [k in keyof a & keyof b]: FindSelected2<a[k], b[k]>;
+}> : never;
+declare type FindSelected2<a, b> = b extends SelectPattern<infer Key> ? {
+    [k in Key]: a;
+} : [a, b] extends [object, object] ? ValueOf<{
+    [k in keyof a & keyof b]: FindSelected3<a[k], b[k]>;
+}> : never;
+declare type FindSelected3<a, b> = b extends SelectPattern<infer Key> ? {
+    [k in Key]: a;
+} : [a, b] extends [object, object] ? ValueOf<{
+    [k in keyof a & keyof b]: FindSelected4<a[k], b[k]>;
+}> : never;
+declare type FindSelected4<a, b> = b extends SelectPattern<infer Key> ? {
+    [k in Key]: a;
+} : [a, b] extends [object, object] ? ValueOf<{
+    [k in keyof a & keyof b]: FindSelected5<a[k], b[k]>;
+}> : never;
+declare type FindSelected5<a, b> = b extends SelectPattern<infer Key> ? {
+    [k in Key]: a;
+} : never;
+declare type ToHandler<a, b, c> = (value: a, selections: UnionToIntersection<FindSelected<a, b>>) => c;
+declare type PatternHandler<a, b extends Pattern<a>, c> = ToHandler<MatchedValue<a, b>, b, c>;
 export declare const when: <a>(predicate: GuardFunction<a>) => GuardPattern<a>;
 export declare const not: <a>(pattern: Pattern<a>) => NotPattern<a>;
+export declare const select: <k extends string>(key: k) => SelectPattern<k>;
 /**
@@ -115,3 +135,3 @@ * ### match
      **/
-    with: <p extends Pattern<a>>(pattern: p, handler: (value: MatchedValue<a, p>) => b) => Match<a, b>;
+    with: <p extends Pattern<a>>(pattern: p, handler: PatternHandler<a, p, b>) => Match<a, b>;
     /**
@@ -118,0 +138,0 @@ * ### Match.when

lib/index.js

 "use strict";
-/**
- * # Pattern matching
- **/
 var __read = (this && this.__read) || function (o, n) {
@@ -26,3 +23,6 @@ var m = typeof Symbol === "function" && o[Symbol.iterator];
 exports.__esModule = true;
-exports.match = exports.not = exports.when = exports.__ = void 0;
+exports.match = exports.select = exports.not = exports.when = exports.__ = void 0;
+/**
+ * # Pattern matching
+ **/
 var PatternType;
@@ -35,2 +35,3 @@ (function (PatternType) {
     PatternType["Not"] = "@match/not";
+    PatternType["Select"] = "@match/select";
 })(PatternType || (PatternType = {}));
@@ -66,2 +67,6 @@ /**
 }); };
+exports.select = function (key) { return ({
+    patternKind: PatternType.Select,
+    key: key
+}); };
 /**
@@ -82,5 +87,19 @@ * ### match
     "with": function (pattern, handler) {
-        return builder(value, __spread(patterns, [[matchPattern(pattern), handler]]));
+        return builder(value, __spread(patterns, [
+            {
+                test: matchPattern(pattern),
+                handler: handler,
+                select: selectWithPattern(pattern)
+            },
+        ]));
     },
-    when: function (predicate, handler) { return builder(value, __spread(patterns, [[predicate, handler]])); },
+    when: function (predicate, handler) {
+        return builder(value, __spread(patterns, [
+            {
+                test: predicate,
+                handler: handler,
+                select: function () { return ({}); }
+            },
+        ]));
+    },
     withWhen: function (pattern, predicate, handler) {
@@ -90,19 +109,28 @@ var doesMatch = function (value) {
         };
-        return builder(value, __spread(patterns, [[doesMatch, handler]]));
+        return builder(value, __spread(patterns, [
+            {
+                test: doesMatch,
+                handler: handler,
+                select: function () { return ({}); }
+            },
+        ]));
     },
     otherwise: function (handler) {
         return builder(value, __spread(patterns, [
-            [matchPattern(exports.__), handler],
+            {
+                test: matchPattern(exports.__),
+                handler: handler,
+                select: function () { return ({}); }
+            },
         ]));
     },
     run: function () {
-        var tupple = patterns.find(function (_a) {
-            var _b = __read(_a, 1), predicate = _b[0];
-            return predicate(value);
+        var entry = patterns.find(function (_a) {
+            var test = _a.test;
+            return test(value);
         });
-        if (!tupple) {
+        if (!entry) {
             throw new Error("Pattern matching error: no pattern matches value " + value);
         }
-        var _a = __read(tupple, 2), mapper = _a[1];
-        return mapper(value);
+        return entry.handler(value, entry.select(value));
     }
@@ -123,5 +151,9 @@ }); };
 };
+var isSelectPattern = function (x) {
+    var pattern = x;
+    return pattern && pattern.patternKind === PatternType.Select;
+};
 // tells us if the value matches a given pattern.
 var matchPattern = function (pattern) { return function (value) {
-    if (pattern === exports.__)
+    if (pattern === exports.__ || isSelectPattern(pattern))
         return true;
@@ -176,1 +208,18 @@ if (pattern === exports.__.string)
 }; };
+var selectWithPattern = function (pattern) { return function (value) {
+    var _a;
+    if (isSelectPattern(pattern))
+        return _a = {}, _a[pattern.key] = value, _a;
+    if (Array.isArray(pattern) && Array.isArray(value))
+        return pattern.length === 1
+            ? value.reduce(function (acc, v) { return Object.assign(acc, selectWithPattern(pattern[0])(v)); }, {})
+            : pattern.length === value.length
+                ? value.reduce(function (acc, v, i) { return Object.assign(acc, selectWithPattern(pattern[i])(v)); }, {})
+                : {};
+    if (isObject(pattern) && isObject(value))
+        return Object.keys(pattern).reduce(function (acc, k) {
+            // @ts-ignore
+            return Object.assign(acc, selectWithPattern(pattern[k])(value[k]));
+        }, {});
+    return {};
+}; };

package.json

 {
   "name": "ts-pattern",
-  "version": "0.1.8",
+  "version": "0.1.9",
   "description": "Typescript pattern matching library",
@@ -5,0 +5,0 @@ "main": "lib/index.js",

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Improved metrics

Total package byte prevSize

21606

increased by19.15%

Number of package files

6

increased by50%

Lines of code

404

increased by28.25%

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