[feat] generics for TS builder; [feat] support row formating as DTO class

Signed-off-by: Anton Nesterov <anton@demiurg.io>

dal/Builder.ts

@@ -36,9 +36,15 @@ type Options = {
     url: string;
 };
 
-export default class Builder {
+
+export default class Builder <
+I extends abstract new (...args: any) => any,
+>{
     private request: Request;
     private url: string;
+    private dtoTemplate: new (...args: any) => any = Object;
+    private methodCalls: Map<string, unknown[]> = new Map(); // one call per method
+    private headerRow: unknown[] | null = null;
     constructor(opts: Options) {
         this.request = {
             id: 0,
@@ -47,78 +53,97 @@ export default class Builder {
         };
         this.url = opts.url;
     }
-    private format(): void {
-        this.request.commands = METHODS.map((method) => {
-            const command = this.request.commands.find((command) => command.method === method);
-            return command;
-        }).filter(Boolean) as Request["commands"];
+    private formatRequest(): void {
+        this.request.commands = []
+        METHODS.forEach((method) => {
+            const args = this.methodCalls.get(method);
+            if (!args) {
+                return;
+            }
+            this.request.commands.push({ method, args });
+        })
     }
-    In(table: string): Builder {
-        this.request.commands.push({ method: "In", args: [table] });
+    private formatRow(data: unknown[]){
+        if (!this.dtoTemplate) {
+            return data;
+        }
+        const instance = new this.dtoTemplate(data);
+        for (const idx in this.headerRow!) {
+            const header = this.headerRow[idx] as string;
+            if (header in instance) {
+                instance[header] = data[idx];
+            }
+        }
+        return instance;
+    }
+    In(table: string): Builder<I> {
+        this.methodCalls.set("In", [table]);
         return this;
     }
-    Find(filter: FindFilter): Builder {
-        this.request.commands.push({ method: "Find", args: [filter] });
+    Find(filter: FindFilter): Builder<I> {
+        this.methodCalls.set("Find", [filter]);
         return this;
     }
-    Select(fields: string[]): Builder {
-        this.request.commands.push({ method: "Select", args: fields });
+    Select(fields: string[]): Builder<I> {
+        this.methodCalls.set("Select", fields);
         return this;
     }
-    Fields(fields: string[]): Builder {
+    Fields(fields: string[]): Builder<I> {
         this.Select(fields);
         return this;
     }
-    Join(...joins: JoinFilter[]): Builder {
-        this.request.commands.push({ method: "Join", args: joins });
+    Join(...joins: JoinFilter[]): Builder<I> {
+        this.methodCalls.set("Join", joins);
         return this;
     }
-    Group(fields: string[]): Builder {
-        this.request.commands.push({ method: "Group", args: fields });
+    Group(fields: string[]): Builder<I> {
+        this.methodCalls.set("Group", fields);
         return this;
     }
-    Sort(fields: SortOptions): Builder {
-        this.request.commands.push({ method: "Sort", args: fields });
+    Sort(fields: SortOptions): Builder<I> {
+        this.methodCalls.set("Sort", [fields]);
         return this;
     }
-    Limit(limit: number): Builder {
-        this.request.commands.push({ method: "Limit", args: [limit] });
+    Limit(limit: number): Builder<I> {
+        this.methodCalls.set("Limit", [limit]);
         return this;
     }
-    Offset(offset: number): Builder {
-        this.request.commands.push({ method: "Offset", args: [offset] });
+    Offset(offset: number): Builder<I> {
+        this.methodCalls.set("Offset", [offset]);
         return this;
     }
-    Delete(): Builder {
-        this.request.commands.push({ method: "Delete", args: [] });
+    Delete(): Builder<I> {
+        this.methodCalls.set("Delete", []);
         return this;
     }
-    Insert(data: Record<string, unknown>): Builder {
-        this.request.commands.push({ method: "Insert", args: [data] });
+    Insert(data: Record<string, unknown>): Builder<I> {
+        this.methodCalls.set("Insert", [data]);
         return this;
     }
-    Set(data: Record<string, unknown>): Builder {
-        this.request.commands.push({ method: "Set", args: [data] });
+    Set(data: Record<string, unknown>): Builder<I> {
+        this.methodCalls.set("Set", [data]);
         return this;
     }
-    Update(data: Record<string, unknown>): Builder {
+    Update(data: Record<string, unknown>): Builder<I> {
         this.Set(data);
         return this;
     }
-    OnConflict(...fields: string[]): Builder {
-        this.request.commands.push({ method: "OnConflict", args: fields });
+    OnConflict(...fields: string[]): Builder<I> {
+        this.methodCalls.set("OnConflict", fields);
         return this;
     }
-    DoUpdate(...fields: string[]): Builder {
-        this.request.commands.push({ method: "DoUpdate", args: fields });
+    DoUpdate(...fields: string[]): Builder<I> {
+        this.methodCalls.delete("DoNothing");
+        this.methodCalls.set("DoUpdate", fields);
         return this;
     }
-    DoNothing(): Builder {
-        this.request.commands.push({ method: "DoNothing", args: [] });
+    DoNothing(): Builder<I> {
+        this.methodCalls.delete("DoUpdate");
+        this.methodCalls.set("DoNothing", []);
         return this;
     }
-    async *Rows() {
-        this.format();
+    async *Rows<T = InstanceType<I>>(): AsyncGenerator<T> {
+        this.formatRequest();
         const response = await fetch(this.url, {
             method: "POST",
             body: new Blob([encodeRequest(this.request)]),
@@ -130,14 +155,27 @@ export default class Builder {
             throw new Error(await response.text());
         }
 
-        for await (const row of decodeRowsIterator(response.body!)) {
-            yield row;
+        const iterator = decodeRowsIterator(response.body!);
+        for await (const row of iterator) {
+            if (this.headerRow === null) {
+                this.headerRow = row.r;
+                await iterator.next();
+                continue;
+            }
+            yield this.formatRow(row.r);
         }
-        this.request = {
-            id: 0,
-            db: this.request.db,
-            commands: [],
-        };
+    }
+    As<T extends new (...args: any) => any>(template: T): Builder<T> {
+        this.dtoTemplate = template;
+        return this;
+    }
+    async Query<T = InstanceType<I>>(): Promise<T[]> {
+        const rows = this.Rows();
+        const result = [];
+        for await (const row of rows) {
+            result.push(row);
+        }
+        return result
     }
     
 }

dal/Protocol.ts

@@ -55,7 +55,6 @@ export async function *decodeRowsIterator(stream: ReadableStream<Uint8Array>): A
     for (;;) {
         const { value, done } = await reader.read();
         if (done) {
-            console.log("done");
             break;
         }
         buf = new Uint8Array([...buf, ...value]);

dal/__test__/builder.test.ts

@@ -0,0 +1,61 @@
+import { test, expect } from "bun:test";
+import { DAL } from ".."
+
+const options = {
+    database: "test.sqlite",
+    url: "http://localhost:8111",
+}
+
+class DTO {
+    id: number = 0;
+    name: string = "";
+    data: string = "";
+    age: number | undefined;
+}
+
+test("Rows iter, no format",  async () => {
+    const dal = new DAL(options);
+    const rows = dal
+        .In("test t")
+        .Find({
+            id: 1,
+        })
+        .Rows<any[]>();
+    for await (const row of rows) {
+        console.log(row);
+        expect(row.length).toBe(3);
+    }
+    expect(true).toBe(true);
+});
+
+test("Rows iter, format",  async () => {
+    const dal = new DAL(options);
+    const rows = dal
+        .In("test t")
+        .Find({
+            id: 1,
+        })
+        .As(DTO)
+        .Rows();
+    for await (const row of rows) {
+        console.log(row);
+        expect(row.id).toBe(1);
+    }
+    expect(true).toBe(true);
+});
+
+test("Query format",  async () => {
+    const dal = new DAL(options);
+    const rows = await dal
+        .In("test t")
+        .Find({
+            id: 1,
+        })
+        .As(DTO)
+        .Query();
+    for (const row of rows) {
+        expect(row.id).toBeDefined();
+        expect(row.age).toBeUndefined();
+    }
+    expect(true).toBe(true);
+});

dal/__test__/protocol.test.ts

@@ -1,24 +0,0 @@
-import { test, expect } from "bun:test";
-import { DAL } from ".."
-
-const options = {
-    database: "test.sqlite",
-    url: "http://localhost:8111",
-}
-
-
-test("Rows iter",  async () => {
-    const dal = new DAL(options);
-    const rows = dal
-        .In("test t")
-        .Find({
-            id: 1,
-        })
-        .Rows();
-    for await (const row of rows) {
-        // console.log(row);
-        //@ts-ignore
-        expect(row.r.length).toBe(3);
-    }
-    expect(true).toBe(true);
-});