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✨ feat(array-methods): add new Array.LastIndexOf method of Array namespace #12

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Merged
AshGreyG merged 5 commits into from
Jul 1, 2025
Merged

✨ feat(array-methods): add new Array.LastIndexOf method of Array namespace #12

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93b57f8
:sparkles: feat(array-methods): add `Array.LastIndexOf` method, simil…
AshGreyG Jul 1, 2025
27dbdad
:test_tube: test(Array.LastIndexOf): add passed tests for `Array.Last…
AshGreyG Jul 1, 2025
c25fbe2
:memo: doc(changelog): add `Array.LastIndexOf` method to next version
AshGreyG Jul 1, 2025
3dc5d0b
:bug: fix(test-script): fix the param separators from `|` to `‖`, the…
AshGreyG Jul 1, 2025
d324535
:test_tube: test(Array.LastIndexOf): add functions and objects array …
AshGreyG Jul 1, 2025
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5 changes: 5 additions & 0 deletions changelog/next.md
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Original file line number Diff line number Diff line change
Expand Up @@ -43,6 +43,11 @@
+ `Array.Pop<Arr, Mode>`
+ `Array.Push<Arr, Element>`

### 2025-07-01 (feature/array-methods → main)

+ Add a new method of `Array` namespace:
+ `Array.LastIndexOf<Arr, T>`

## ⚡ Improvements

## 🐦‍🔥 No longer broken
25 changes: 25 additions & 0 deletions lib/Array/index.d.ts
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Expand Up @@ -260,6 +260,31 @@ export type IndexOf<
: IndexOf<Rest, T, [...Count, 0]>
: -1;

/**
* This method returns the last encounter index of element `T` in array `Arr`.
*
* @param Arr The array to be checked.
* @param T The element to check the last encounter index.
* @param Count Middle variable to store the scanning state.
* @returns The last encounter index of element `T` in array `Arr`.
*
* @example
* type LastIndex1 = Array.LastIndexOf<[1, 2, 1, 22, 3], 1>; // 2
* type LastIndex2 = Array.LastIndexOf<[], 1>; // -1
* type LastIndex3 = Array.LastIndexOf<[1], 1>; // 0
*/
export type LastIndexOf<
Arr extends unknown[],
T extends unknown,
Count extends 0[] = CreateArrayFromLength<Arr["length"], 0>
> = Arr extends [...infer Rest, infer L]
? Equal<L, T> extends true
? Integer.Dec<Count["length"]>
: Count extends [...infer RestCount extends 0[], 0]
? LastIndexOf<Rest, T, RestCount>
: -1
: -1;

/**
* This method is like `Array.prototype.join`, it creates and returns a new string by
* concatenating all of the elements in this array, separated by commas or a specified
Expand Down
8 changes: 8 additions & 0 deletions test/lib-Array.test.ts
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Expand Up @@ -89,4 +89,12 @@ type CaseLibArray = [
Expect<Equal<Array.At<[], -1>, never>>,
Expect<Equal<Array.At<[], 0>, never>>,

// Array.LastIndexOf
Expect<Equal<Array.LastIndexOf<[1,2,1,2,1,3,4], 1>, 4>>,
Expect<Equal<Array.LastIndexOf<[], 1>, -1>>,
Expect<Equal<Array.LastIndexOf<[1,2,3], 0>, -1>>,
Expect<Equal<Array.LastIndexOf<[[],[[]],[],[]], [[]]>, 1>>,
Comment on lines +93 to +96
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suggestion (testing): Missing tests for edge cases with complex types and repeated non-primitive values.

Add tests for arrays with objects, symbols, functions, and cases like different object references or NaN to ensure correct LastIndexOf behavior with complex types and tricky equality scenarios.

Expect<Equal<Array.LastIndexOf<[()=>{},(a:string)=>{},(b:string)=>{},()=>{}], (c:string)=>{}>, 2>>,
Expect<Equal<Array.LastIndexOf<[{a:string},{},{b:string}], {}>, 1>>,

]
113 changes: 57 additions & 56 deletions test/script/lib-gen.sh
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Original file line number Diff line number Diff line change
Expand Up @@ -4,60 +4,61 @@ ROOT_DIR=$(dirname "$(realpath "$0")")/../..
TEST_DIR="${ROOT_DIR}/test"

declare -A test_cases=(
["Integer.IsNegative"]="-2:true 0:false 9:false"
["Integer.IsPositive"]="-2:false 0:false 9:true"
["Integer.IsZero"]="-2:false 0:true 9:false"
["Integer.Opposite"]="-2:2 0:0 20:-20"
["Integer.Lower"]="2|1:false 1|2:true 2|-1:false -1|2:true -3|-2:true -2|-3:false -1|0:true 2|0:false 0|3:true 0|-3:false 0|0:false 2|2:false -2|-2:false"
["Integer.Greater"]="2|1:true 1|2:false 2|-1:true -1|2:false -3|-2:false -2|-3:true -1|0:false 2|0:true 0|3:false 0|-3:true 0|0:false 2|2:false -2|-2:false"
["Integer.Eq"]="2|1:false 1|2:false 2|-1:false -1|2:false -3|-2:false -2|-3:false -1|0:false 2|0:false 0|3:false 0|-3:false 0|0:true 2|2:true -2|-2:true"
["Integer.Neq"]="2|1:true 1|2:true 2|-1:true -1|2:true -3|-2:true -2|-3:true -1|0:true 2|0:true 0|3:true 0|-3:true 0|0:false 2|2:false -2|-2:false"
["Integer.LowerEq"]="2|1:false 1|2:true 2|-1:false -1|2:true -3|-2:true -2|-3:false -1|0:true 2|0:false 0|3:true 0|-3:false 0|0:true 2|2:true -2|-2:true"
["Integer.GreaterEq"]="2|1:true 1|2:false 2|-1:true -1|2:false -3|-2:false -2|-3:true -1|0:false 2|0:true 0|3:false 0|-3:true 0|0:true 2|2:true -2|-2:true"
["Integer.Add"]="2|3:5 -2|2:0 -2|-6:-8 3|-3:0 3|-2:1 -2|1:-1 0|0:0 -2|0:-2 2|0:2 0|20:20 0|-30:-30"
["Integer.Inc"]="2:3 0:1 -1:0 -30:-29"
["Integer.Sub"]="2|3:-1 3|2:1 -2|3:-5 -2|-3:1 -9|-2:-7 2|0:2 -3|0:-3 0|2:-2 0|-3:3 0|0:0 2|2:0 -3|-3:0"
["Integer.Dec"]="2:1 0:-1 1:0 -3:-4"
["Integer.Divide"]="2|3:0 4|2:2 9|-3:-3 9|-2:-4 9|0:never -2|-3:0 -4|2:-2 4|4:1 4|-4:-1 -4|-4:1"
["Integer.Mod"]="2|2:0 3|2:1 -3|-2:1 -3|2:-1 9|5:4"
["Integer.IsOdd"]="1:true 2:false 0:false -3:true -19:true 20:false"
["Integer.IsEven"]="1:false 0:true -22:true 19:false"

["Array.CreateArrayFromLength"]="2:[undefined,undefined] 3|string:[string,string,string] 0:[] -1:[]"
["Array.At"]="[1,2,3]|2:3 [1,2,3,4]|0|:1 []|1:never []|-1:never []|0:never"
["Array.Concat"]="[1,2,3]|[2,3,1]:[1,2,3,2,3,1]"
["Array.MultipleConcat"]="[[1,2,3],[4,2,3],[undefined,true]]:[1,2,3,4,2,3,undefined,true] [[],[1],[],[2]]:[1,2] [[[2]],[1]]:[[2],1]"
["Array.Fill"]="[1,2,3]|\"3\":[\"3\",\"3\",\"3\"] [0,9,1]|\"1\"|1|2:[0,\"1\",1] [\"head\",9,1]|true|1:[\"head\",true,true] [1,2,3]|\"3\"|2|1:[1,2,3] [1,2,3]|\"3\"|-4|2:[\"3\",\"3\",3] [1,2,3]|\"3\"|-2|3:[1,\"3\",\"3\"] [1,2,3]|\"3\"|7|2:[1,2,3] [1,2,3]|\"3\"|1|-1:[1,\"3\",3]"
["Array.IsFlatten"]="[1,2,3]:true []:true [[]]:false [1,[2],3]:false [[],1,2]:false [1,[1,2,[]],undefined]:false"
["Array.Flat"]="[1,2,3]:[1,2,3] [1,2,3,[]]:[1,2,3] [1,2,[3]]:[1,2,3] [1,2,[3,[0]]]:[1,2,3,0] []:[] [[]]:[] [[[1]]]:[1]"
["Array.Includes"]="[1,2,3]|1:true [1,2,3]|-1:false []|\"\":false [\"\"]|\"\":true [[]]|[]:true [[1]]|1:false"
["Array.IndexOf"]="[1,2,3]|1:0 [1,[2],3]|[2]:1 []|0:-1 [1,2,3]|4:-1 [1,2,1]|1:0"
["Array.Join"]="[1,2,3]:\"1,2,3\" [-1,\".\",9]|\"-\":\"-1-.-9\" [1,2,3]|\"\":\"123\""
["Array.Pop"]="[1,2,3]:[1,2] [1]|\"get-rest\":[] []|\"get-rest\":never [1,2,3]|\"get-pop-element\":3 [1]|\"get-pop-element\":1 []|\"get-pop-element\":never"
["Array.Push"]="[1,2,3]|\"1\":[1,2,3,\"1\"] []|1:[1] []|[]:[[]]"

["BigInteger.ToString"]="2n:\"2\" -2n:\"-2\" 0n:\"0\""
["BigInteger.IsNegative"]="-23n:true 26n:false 0n:false"
["BigInteger.IsPositive"]="90n:true 0n:false -8n:false"
["BigInteger.IsZero"]="0n:true 29n:false -2n:false"
["BigInteger.Opposite"]="0n:0n 23n:-23n -12n:12n"
["BigInteger.Eq"]="0n|0n:true -12n|-12n:true 23n|22n:false 23n|-23n:false"
["BigInteger.Lower"]="23n|123n:true 23n|23n:false 1234n|1235n:true -123n|90n:true 123n|-90n:false 0n|0n:false -2n|-2n:false 12345n|12345n:false"

["String.Length"]="\"abs\":3 \"\":0 \"2222_2222_2222_2222_2222\":24"
["String.At"]="\"123456789\"|0:\"1\" \"123456789\"|2:\"3\" \"123456789\"|-3:\"7\" \"123456789\"|100:never"
["String.Concat"]="[\"12\",\"ab\"]:\"12ab\" [\"love\"]:\"love\" []:\"\""
["String.SubString"]="\"LoveYouHuaier\":\"LoveYouHuaier\" \"LoveYouHuaier\"|4:\"YouHuaier\" \"LoveYouHuaier\"|4|9:\"YouHu\" \"LoveYouHuaier\"|3|-2:\"eYouHuai\" \"LoveYouHuaier\"|-7|-2:\"uHuai\" \"LoveYouHuaier\"|0|0:\"\" \"LoveYouHuaier\"|-1|-1:\"\" \"LoveYouHuaier\"|8|7:\"\""
["String.EndsWith"]="\"What?\"|\"?\":true \"What?\"|\"What?\":true \"What?\"|\"SoWhat?\":false \"What?\"|\"t?\":true \"What?\"|\"W?\":false \"What?\"|\"\":true \"\"|\"test\":false \"\"|\"\":true \"What?\"|\"?\"|5:true \"What?\"|\"t?\"|3:false \"\"|\"\"|2:true"
["String.Includes"]="\"AshGrey\"|\"Ash\":true \"AshGrey\"|\"A\":true \"AshGrey\"|\"a\":false \"AshGrey\"|\"\":true \"AshGrey\"|\"Ash\"|0:true \"AshGrey\"|\"Ash\"|1:false \"AshGrey\"|\"Ash\"|-1:true"

["Boolean.And"]="false|false:false false|true:false true|false:false true|true:true"
["Boolean.Or"]="false|false:false false|true:true true|false:true true|true:true"
["Boolean.Nor"]="false:true true:false"
["Boolean.Nand"]="false|false:true false|true:true true|false:true true|true:false"
["Boolean.Nor"]="false|false:true false|true:false true|false:false true|true:false"
["Boolean.MultipleAnd"]="[true,true,true]:true [true,false,true]:false [false,false,false]:false"
["Boolean.MultipleOr"]="[true,true,true]:true [true,false,false]:true [false,false,false]:false"
["Integer.IsNegative"]="-2∷true 0∷false 9∷false"
["Integer.IsPositive"]="-2∷false 0∷false 9∷true"
["Integer.IsZero"]="-2∷false 0∷true 9∷false"
["Integer.Opposite"]="-2∷2 0∷0 20∷-20"
["Integer.Lower"]="2‖1∷false 1‖2∷true 2‖-1∷false -1‖2∷true -3‖-2∷true -2‖-3∷false -1‖0∷true 2‖0∷false 0‖3∷true 0‖-3∷false 0‖0∷false 2‖2∷false -2‖-2∷false"
["Integer.Greater"]="2‖1∷true 1‖2∷false 2‖-1∷true -1‖2∷false -3‖-2∷false -2‖-3∷true -1‖0∷false 2‖0∷true 0‖3∷false 0‖-3∷true 0‖0∷false 2‖2∷false -2‖-2∷false"
["Integer.Eq"]="2‖1∷false 1‖2∷false 2‖-1∷false -1‖2∷false -3‖-2∷false -2‖-3∷false -1‖0∷false 2‖0∷false 0‖3∷false 0‖-3∷false 0‖0∷true 2‖2∷true -2‖-2∷true"
["Integer.Neq"]="2‖1∷true 1‖2∷true 2‖-1∷true -1‖2∷true -3‖-2∷true -2‖-3∷true -1‖0∷true 2‖0∷true 0‖3∷true 0‖-3∷true 0‖0∷false 2‖2∷false -2‖-2∷false"
["Integer.LowerEq"]="2‖1∷false 1‖2∷true 2‖-1∷false -1‖2∷true -3‖-2∷true -2‖-3∷false -1‖0∷true 2‖0∷false 0‖3∷true 0‖-3∷false 0‖0∷true 2‖2∷true -2‖-2∷true"
["Integer.GreaterEq"]="2‖1∷true 1‖2∷false 2‖-1∷true -1‖2∷false -3‖-2∷false -2‖-3∷true -1‖0∷false 2‖0∷true 0‖3∷false 0‖-3∷true 0‖0∷true 2‖2∷true -2‖-2∷true"
["Integer.Add"]="2‖3∷5 -2‖2∷0 -2‖-6∷-8 3‖-3∷0 3‖-2∷1 -2‖1∷-1 0‖0∷0 -2‖0∷-2 2‖0∷2 0‖20∷20 0‖-30∷-30"
["Integer.Inc"]="2∷3 0∷1 -1∷0 -30∷-29"
["Integer.Sub"]="2‖3∷-1 3‖2∷1 -2‖3∷-5 -2‖-3∷1 -9‖-2∷-7 2‖0∷2 -3‖0∷-3 0‖2∷-2 0‖-3∷3 0‖0∷0 2‖2∷0 -3‖-3∷0"
["Integer.Dec"]="2∷1 0∷-1 1∷0 -3∷-4"
["Integer.Divide"]="2‖3∷0 4‖2∷2 9‖-3∷-3 9‖-2∷-4 9‖0∷never -2‖-3∷0 -4‖2∷-2 4‖4∷1 4‖-4∷-1 -4‖-4∷1"
["Integer.Mod"]="2‖2∷0 3‖2∷1 -3‖-2∷1 -3‖2∷-1 9‖5∷4"
["Integer.IsOdd"]="1∷true 2∷false 0∷false -3∷true -19∷true 20∷false"
["Integer.IsEven"]="1∷false 0∷true -22∷true 19∷false"

["Array.CreateArrayFromLength"]="2∷[undefined,undefined] 3‖string∷[string,string,string] 0∷[] -1∷[]"
["Array.At"]="[1,2,3]‖2∷3 [1,2,3,4]‖0‖∷1 []‖1∷never []‖-1∷never []‖0∷never"
["Array.Concat"]="[1,2,3]‖[2,3,1]∷[1,2,3,2,3,1]"
["Array.MultipleConcat"]="[[1,2,3],[4,2,3],[undefined,true]]∷[1,2,3,4,2,3,undefined,true] [[],[1],[],[2]]∷[1,2] [[[2]],[1]]∷[[2],1]"
["Array.Fill"]="[1,2,3]‖\"3\"∷[\"3\",\"3\",\"3\"] [0,9,1]‖\"1\"‖1‖2∷[0,\"1\",1] [\"head\",9,1]‖true‖1∷[\"head\",true,true] [1,2,3]‖\"3\"‖2‖1∷[1,2,3] [1,2,3]‖\"3\"‖-4‖2∷[\"3\",\"3\",3] [1,2,3]‖\"3\"‖-2‖3∷[1,\"3\",\"3\"] [1,2,3]‖\"3\"‖7‖2∷[1,2,3] [1,2,3]‖\"3\"‖1‖-1∷[1,\"3\",3]"
["Array.IsFlatten"]="[1,2,3]∷true []∷true [[]]∷false [1,[2],3]∷false [[],1,2]∷false [1,[1,2,[]],undefined]∷false"
["Array.Flat"]="[1,2,3]∷[1,2,3] [1,2,3,[]]∷[1,2,3] [1,2,[3]]∷[1,2,3] [1,2,[3,[0]]]∷[1,2,3,0] []∷[] [[]]∷[] [[[1]]]∷[1]"
["Array.Includes"]="[1,2,3]‖1∷true [1,2,3]‖-1∷false []‖\"\"∷false [\"\"]‖\"\"∷true [[]]‖[]∷true [[1]]‖1∷false"
["Array.IndexOf"]="[1,2,3]‖1∷0 [1,[2],3]‖[2]∷1 []‖0∷-1 [1,2,3]‖4∷-1 [1,2,1]‖1∷0"
["Array.LastIndexOf"]="[1,2,1,2,1,3,4]‖1∷4 []‖1∷-1 [1,2,3]‖0∷-1 [[],[[]],[],[]]‖[[]]∷1 [()=>{},(a:string)=>{},(b:string)=>{},()=>{}]‖(c:string)=>{}∷2 [{a:string},{},{b:string}]‖{}∷1"
["Array.Join"]="[1,2,3]∷\"1,2,3\" [-1,\".\",9]‖\"-\"∷\"-1-.-9\" [1,2,3]‖\"\"∷\"123\""
["Array.Pop"]="[1,2,3]∷[1,2] [1]‖\"get-rest\"∷[] []‖\"get-rest\"∷never [1,2,3]‖\"get-pop-element\"∷3 [1]‖\"get-pop-element\"∷1 []‖\"get-pop-element\"∷never"
["Array.Push"]="[1,2,3]‖\"1\"∷[1,2,3,\"1\"] []‖1∷[1] []‖[]∷[[]]"

["BigInteger.ToString"]="2n∷\"2\" -2n∷\"-2\" 0n∷\"0\""
["BigInteger.IsNegative"]="-23n∷true 26n∷false 0n∷false"
["BigInteger.IsPositive"]="90n∷true 0n∷false -8n∷false"
["BigInteger.IsZero"]="0n∷true 29n∷false -2n∷false"
["BigInteger.Opposite"]="0n∷0n 23n∷-23n -12n∷12n"
["BigInteger.Eq"]="0n‖0n∷true -12n‖-12n∷true 23n‖22n∷false 23n‖-23n∷false"
["BigInteger.Lower"]="23n‖123n∷true 23n‖23n∷false 1234n‖1235n∷true -123n‖90n∷true 123n‖-90n∷false 0n‖0n∷false -2n‖-2n∷false 12345n‖12345n∷false"

["String.Length"]="\"abs\"∷3 \"\"∷0 \"2222_2222_2222_2222_2222\"∷24"
["String.At"]="\"123456789\"‖0∷\"1\" \"123456789\"‖2∷\"3\" \"123456789\"‖-3∷\"7\" \"123456789\"‖100∷never"
["String.Concat"]="[\"12\",\"ab\"]∷\"12ab\" [\"love\"]∷\"love\" []∷\"\""
["String.SubString"]="\"LoveYouHuaier\"∷\"LoveYouHuaier\" \"LoveYouHuaier\"‖4∷\"YouHuaier\" \"LoveYouHuaier\"‖4‖9∷\"YouHu\" \"LoveYouHuaier\"‖3‖-2∷\"eYouHuai\" \"LoveYouHuaier\"‖-7‖-2∷\"uHuai\" \"LoveYouHuaier\"‖0‖0∷\"\" \"LoveYouHuaier\"‖-1‖-1∷\"\" \"LoveYouHuaier\"‖8‖7∷\"\""
["String.EndsWith"]="\"What?\"‖\"?\"∷true \"What?\"‖\"What?\"∷true \"What?\"‖\"SoWhat?\"∷false \"What?\"‖\"t?\"∷true \"What?\"‖\"W?\"∷false \"What?\"‖\"\"∷true \"\"‖\"test\"∷false \"\"‖\"\"∷true \"What?\"‖\"?\"‖5∷true \"What?\"‖\"t?\"‖3∷false \"\"‖\"\"‖2∷true"
["String.Includes"]="\"AshGrey\"‖\"Ash\"∷true \"AshGrey\"‖\"A\"∷true \"AshGrey\"‖\"a\"∷false \"AshGrey\"‖\"\"∷true \"AshGrey\"‖\"Ash\"‖0∷true \"AshGrey\"‖\"Ash\"‖1∷false \"AshGrey\"‖\"Ash\"‖-1∷true"

["Boolean.And"]="false‖false∷false false‖true∷false true‖false∷false true‖true∷true"
["Boolean.Or"]="false‖false∷false false‖true∷true true‖false∷true true‖true∷true"
["Boolean.Nor"]="false∷true true∷false"
["Boolean.Nand"]="false‖false∷true false‖true∷true true‖false∷true true‖true∷false"
["Boolean.Nor"]="false‖false∷true false‖true∷false true‖false∷false true‖true∷false"
["Boolean.MultipleAnd"]="[true,true,true]∷true [true,false,true]∷false [false,false,false]∷false"
["Boolean.MultipleOr"]="[true,true,true]∷true [true,false,false]∷true [false,false,false]∷false"
)

function repeat {
Expand Down Expand Up @@ -96,8 +97,8 @@ for test_name in "${!test_cases[@]}"; do

echo " // ${test_name}" >> "$output_file"
for pair in ${test_cases[$test_name]}; do
IFS=":" read -r params expect <<< "$pair"
IFS="|" read -ra args <<< "$params"
IFS="∷" read -r params expect <<< "$pair"
IFS="‖" read -ra args <<< "$params"

# echo "🐵 Check Middle Args ${args[@]}"

Expand Down