refactor(collections): prepare for noUncheckedIndexedAccess (denola…

…nd#4268)

collections/drop_last_while.ts

@@ -25,7 +25,7 @@ export function dropLastWhile<T>(
   predicate: (el: T) => boolean,
 ): T[] {
   let offset = array.length;
-  while (0 < offset && predicate(array[offset - 1])) offset--;
+  while (0 < offset && predicate(array[offset - 1] as T)) offset--;
 
   return array.slice(0, offset);
 }

collections/drop_while.ts

@@ -23,7 +23,7 @@ export function dropWhile<T>(
   let offset = 0;
   const length = array.length;
 
-  while (length > offset && predicate(array[offset])) {
+  while (length > offset && predicate(array[offset] as T)) {
     offset++;
   }
 

collections/filter_keys.ts

@@ -31,11 +31,10 @@ export function filterKeys<T>(
   predicate: (key: string) => boolean,
 ): Record<string, T> {
   const ret: Record<string, T> = {};
-  const keys = Object.keys(record);
 
-  for (const key of keys) {
+  for (const [key, value] of Object.entries(record)) {
     if (predicate(key)) {
-      ret[key] = record[key];
+      ret[key] = value;
     }
   }
 

collections/map_keys.ts

@@ -30,12 +30,10 @@ export function mapKeys<T>(
   transformer: (key: string) => string,
 ): Record<string, T> {
   const ret: Record<string, T> = {};
-  const keys = Object.keys(record);
 
-  for (const key of keys) {
+  for (const [key, value] of Object.entries(record)) {
     const mappedKey = transformer(key);
-
-    ret[mappedKey] = record[key];
+    ret[mappedKey] = value;
   }
 
   return ret;

collections/map_keys_test.ts

@@ -134,7 +134,7 @@ Deno.test({
           "/home/deno/food.txt": "Plants, preferably fruit",
           "/home/deno/other-dinos.txt": "Noderaptor, Pythonoctorus",
         },
-        (path) => path.split("/").slice(-1)[0],
+        (path) => (path.split("/").slice(-1) as [string])[0],
       ],
       {
         "food.txt": "Plants, preferably fruit",

collections/permutations.ts

@@ -39,11 +39,11 @@ export function permutations<T>(inputArray: Iterable<T>): T[][] {
   let i = 1;
 
   while (i < k) {
-    if (c[i] < i) {
+    if (c[i]! < i) {
       if (i % 2 === 0) {
-        [array[0], array[i]] = [array[i], array[0]];
+        [array[0], array[i]] = [array[i], array[0]] as [T, T];
       } else {
-        [array[c[i]], array[i]] = [array[i], array[c[i]]];
+        [array[c[i]!], array[i]] = [array[i], array[c[i]!]] as [T, T];
       }
 
       ret.push([...array]);

collections/sort_by.ts

@@ -126,15 +126,15 @@ export function sortBy<T>(
   const selectors = new Array<ReturnType<typeof selector> | null>(len);
   const order = options?.order ?? "asc";
 
-  for (let i = 0; i < len; i++) {
-    indexes[i] = i;
-    const s = selector(array[i]);
-    selectors[i] = Number.isNaN(s) ? null : s;
-  }
+  array.forEach((item, idx) => {
+    indexes[idx] = idx;
+    const s = selector(item);
+    selectors[idx] = Number.isNaN(s) ? null : s;
+  });
 
   indexes.sort((ai, bi) => {
-    let a = selectors[ai];
-    let b = selectors[bi];
+    let a = selectors[ai]!;
+    let b = selectors[bi]!;
     if (order === "desc") {
       [a, b] = [b, a];
     }
@@ -144,7 +144,7 @@ export function sortBy<T>(
   });
 
   for (let i = 0; i < len; i++) {
-    (indexes as unknown as T[])[i] = array[indexes[i]];
+    (indexes as unknown as T[])[i] = array[indexes[i] as number] as T;
   }
 
   return indexes as unknown as T[];

collections/take_last_while.ts

@@ -23,7 +23,7 @@ export function takeLastWhile<T>(
   predicate: (el: T) => boolean,
 ): T[] {
   let offset = array.length;
-  while (0 < offset && predicate(array[offset - 1])) offset--;
+  while (0 < offset && predicate(array[offset - 1] as T)) offset--;
 
   return array.slice(offset, array.length);
 }

collections/take_while.ts

@@ -25,7 +25,7 @@ export function takeWhile<T>(
   let offset = 0;
   const length = array.length;
 
-  while (length > offset && predicate(array[offset])) {
+  while (length > offset && predicate(array[offset] as T)) {
     offset++;
   }