Maintain types better through lambda and list

Fixes #249
graphile · Mar 21, 2023 · 0049f89 · 0049f89
1 parent c5a1273
commit 0049f89
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Showing 6 changed files with 41 additions and 30 deletions.
diff --git a/grafast/dataplan-pg/src/examples/exampleSchema.ts b/grafast/dataplan-pg/src/examples/exampleSchema.ts
@@ -3231,8 +3231,8 @@ export function makeExampleSchema(
           any,
           any
         >,
-      number[],
-      ListStep<ExecutableStep<number>[]>
+      readonly number[],
+      ListStep<readonly ExecutableStep<any>[]>
     > => ({
       Person: {
         match: (v) => v[0] != null,

diff --git a/grafast/dataplan-pg/src/steps/pgSelect.ts b/grafast/dataplan-pg/src/steps/pgSelect.ts
@@ -1716,16 +1716,20 @@ and ${sql.indent(sql.parens(condition(i + 1)))}`}
 
       const $lower =
         this.lowerIndexStepId != null
-          ? this.getDep(this.lowerIndexStepId)
+          ? (this.getDep(this.lowerIndexStepId) as ExecutableStep<
+              number | null | undefined
+            >)
           : constant(null);
       const $upper =
         this.upperIndexStepId != null
-          ? this.getDep(this.upperIndexStepId)
+          ? (this.getDep(this.upperIndexStepId) as ExecutableStep<
+              number | null | undefined
+            >)
           : constant(null);
 
       const limitAndOffsetLambda = lambda(
         list([$lower, $upper]),
-        ([cursorLower, cursorUpper]: Array<number | null>) => {
+        ([cursorLower, cursorUpper]) => {
           /** lower bound - exclusive (1-indexed) */
           let lower = 0;
           /** upper bound - exclusive (1-indexed) */

diff --git a/grafast/dataplan-pg/src/steps/pgUnionAll.ts b/grafast/dataplan-pg/src/steps/pgUnionAll.ts
@@ -108,7 +108,7 @@ function parseCursor(cursor: string | null) {
 }
 parseCursor.isSyncAndSafe = true; // Optimization
 
-function add([a, b]: [a: number, b: number]): number {
+function add([a, b]: readonly [a: number, b: number]): number {
   return a + b;
 }
 add.isSyncAndSafe = true;
@@ -1310,16 +1310,20 @@ and ${condition(i + 1)}`}
 
       const $lower =
         this.lowerIndexStepId != null
-          ? this.getDep(this.lowerIndexStepId)
+          ? (this.getDep(this.lowerIndexStepId) as ExecutableStep<
+              number | null | undefined
+            >)
           : constant(null);
       const $upper =
         this.upperIndexStepId != null
-          ? this.getDep(this.upperIndexStepId)
+          ? (this.getDep(this.upperIndexStepId) as ExecutableStep<
+              number | null | undefined
+            >)
           : constant(null);
 
       const limitAndOffsetLambda = lambda(
         list([$lower, $upper]),
-        ([cursorLower, cursorUpper]: Array<number | null>) => {
+        ([cursorLower, cursorUpper]) => {
           /** lower bound - exclusive (1-indexed) */
           let lower = 0;
           /** upper bound - exclusive (1-indexed) */
@@ -1379,13 +1383,13 @@ and ${condition(i + 1)}`}
         true,
       );
       this.limitAndOffsetId = this.addDependency(limitAndOffsetLambda);
-      const limitLambda = access<number>(limitAndOffsetLambda, [0]);
-      const offsetLambda = access<number>(limitAndOffsetLambda, [1]);
-      const limitPlusOffsetLambda = lambda([limitLambda, offsetLambda], add);
+      const $limitLambda = access<number>(limitAndOffsetLambda, [0]);
+      const $offsetLambda = access<number>(limitAndOffsetLambda, [1]);
+      const limitPlusOffsetLambda = lambda([$limitLambda, $offsetLambda], add);
       this.limitAndOffsetSQL = sql`\nlimit ${this.placeholder(
-        limitLambda,
+        $limitLambda,
         TYPES.int,
-      )}\noffset ${this.placeholder(offsetLambda, TYPES.int)}`;
+      )}\noffset ${this.placeholder($offsetLambda, TYPES.int)}`;
       this.innerLimitSQL = sql`\nlimit ${this.placeholder(
         limitPlusOffsetLambda,
         TYPES.int,

diff --git a/grafast/grafast/src/interfaces.ts b/grafast/grafast/src/interfaces.ts
@@ -814,3 +814,9 @@ export interface JSONObject {
   [key: string]: JSONValue;
 }
 export interface JSONArray extends Array<JSONValue> {}
+
+export type UnwrapPlanTuple<
+  /* const */ TIn extends readonly ExecutableStep<any>[],
+> = {
+  [Index in keyof TIn]: TIn[Index] extends ExecutableStep<infer U> ? U : never;
+} & { length: number };
diff --git a/grafast/grafast/src/steps/lambda.ts b/grafast/grafast/src/steps/lambda.ts
@@ -1,4 +1,4 @@
-import type { ExecutionExtra, PromiseOrDirect } from "../interfaces.js";
+import type { ExecutionExtra, PromiseOrDirect, UnwrapPlanTuple } from "../interfaces.js";
 import type { ExecutableStep } from "../step.js";
 import { UnbatchedExecutableStep } from "../step.js";
 import { list } from "./list.js";
@@ -50,12 +50,15 @@ export class LambdaStep<TIn, TOut> extends UnbatchedExecutableStep<TOut> {
  * callback. Note: if you need to pass more than one value, pass a `ListStep`
  * as the `$plan` argument.
  */
-function lambda<TIn extends [...any[]], TOut>(
-  plans: { [Index in keyof TIn]: ExecutableStep<TIn[Index]> },
-  fn: (value: TIn) => PromiseOrDirect<TOut>,
+function lambda<const TIn extends readonly ExecutableStep<any>[], TOut>(
+  plans: TIn,
+  fn: (value: UnwrapPlanTuple<TIn>) => PromiseOrDirect<TOut>,
   isSyncAndSafe?: boolean,
-): LambdaStep<TIn, TOut>;
-function lambda<TIn, TOut>(
+): LambdaStep<
+  UnwrapPlanTuple<TIn>,
+  TOut
+>;
+function lambda<const TIn extends any, TOut>(
   $plan: ExecutableStep<TIn> | null | undefined,
   fn: (value: TIn) => PromiseOrDirect<TOut>,
   isSyncAndSafe?: boolean,

diff --git a/grafast/grafast/src/steps/list.ts b/grafast/grafast/src/steps/list.ts
@@ -1,15 +1,9 @@
-import type { ExecutionExtra } from "../interfaces.js";
+import type { ExecutionExtra, UnwrapPlanTuple } from "../interfaces.js";
 import type { ExecutableStep } from "../step.js";
 import { UnbatchedExecutableStep } from "../step.js";
 
-type UnwrapPlanTuple<TPlanTuple extends readonly ExecutableStep<any>[]> = [
-  ...(TPlanTuple extends readonly ExecutableStep<infer U>[]
-    ? readonly U[]
-    : never)
-];
-
 export class ListStep<
-  TPlanTuple extends readonly ExecutableStep<any>[],
+  const TPlanTuple extends readonly ExecutableStep<any>[],
 > extends UnbatchedExecutableStep<UnwrapPlanTuple<TPlanTuple>> {
   static $$export = {
     moduleName: "grafast",
@@ -18,7 +12,7 @@ export class ListStep<
   isSyncAndSafe = true;
   allowMultipleOptimizations = true;
 
-  constructor(list: readonly [...TPlanTuple]) {
+  constructor(list: TPlanTuple) {
     super();
     for (let i = 0, l = list.length; i < l; i++) {
       this.addDependency(list[i]);
@@ -95,7 +89,7 @@ export class ListStep<
  * Takes a list of plans and turns it into a single plan that represents the
  * list of their values.
  */
-export function list<TPlanTuple extends ExecutableStep<any>[]>(
+export function list<const TPlanTuple extends readonly ExecutableStep<any>[]>(
   list: TPlanTuple,
 ): ListStep<TPlanTuple> {
   return new ListStep<TPlanTuple>(list);