feat: populate database function

src/db/index.ts

@@ -0,0 +1,79 @@
+import { logError, logSuccess, projectRoot } from "../utils";
+import fs from "fs";
+import path from "path";
+import { Client, QueryResult } from "pg";
+
+export const tableExists = async (db: Client): Promise<boolean> => {
+    const result = await db
+        .query(
+            "SELECT EXISTS (SELECT * FROM information_schema.tables WHERE table_name = 'words');"
+        )
+        .catch((err) => err);
+
+    return result.rows[0].exists;
+};
+
+// used for generating param query string
+// expand(rowCount: 3, columnCount: 2) returns "($1, $2), ($3, $4), ($5, $6)"
+function expand(rowCount: number, columnCount = 1, startAt = 1) {
+    var index = startAt;
+    return Array(rowCount)
+        .fill(0)
+        .map(
+            (v) =>
+                `(${Array(columnCount)
+                    .fill(0)
+                    .map((v) => `$${index++}`)
+                    .join(", ")})`
+        )
+        .join(", ");
+}
+
+export const populateDB = async (db: Client) => {
+    let filename = "words.txt";
+    let filepath = path.join(projectRoot, filename);
+
+    // check for source file
+    if (!fs.existsSync(filepath)) {
+        logError(
+            "Could not find `okiba/words.txt` for populating the database!\n"
+        );
+        process.exit(1);
+    }
+
+    await db
+        .query(
+            "CREATE TABLE words (id SERIAL PRIMARY KEY, val VARCHAR NOT NULL, taken BOOLEAN DEFAULT 'f');"
+        )
+        .catch((err) => err);
+
+    fs.readFile(
+        filepath,
+        { encoding: "utf-8" },
+        async (err: Error | null, data: string) => {
+            if (err != null) {
+                logError(err.message);
+                throw err;
+            }
+
+            let arr: Array<string> = data.split("\r\n");
+
+            // 1k entries per query
+            const chunkSize = 1000;
+            for (let i = 0; i < arr.length; i += chunkSize) {
+                const chunk: Array<string> = arr.slice(i, i + chunkSize);
+
+                const queryStr = {
+                    text: `INSERT INTO words (val) VALUES ${expand(
+                        chunk.length
+                    )}`,
+                    values: chunk,
+                };
+
+                await db.query(queryStr);
+            }
+        }
+    );
+
+    logSuccess("Successfully populated the database!");
+};