Setup for postgres database & schema for blogposts.

api/database/scripts/seedDatabase.js

@@ -0,0 +1,90 @@
+const path = require("path");
+const fs = require("fs");
+const fsPromises = require("fs/promises");
+
+if (global.__base == undefined)
+  global.__base = path.join(__dirname, "../..");
+
+const db = require("../index.js");
+
+class SeedStep {
+  constructor(filepath) {
+    this.filepath = filepath;
+    this.filename = filepath.split("/").pop();
+  };
+
+  readData() {
+    this.data = JSON.parse(fs.readFileSync(this.filepath, 'utf-8'));
+  };
+
+  get isApplied() {
+    const query = `SELECT * FROM seed WHERE filename = $1`;
+    return db.query(query, [ this.filename ])
+      .then(resp => resp == 1 ? true : false)
+  }
+
+  commitStepToDb() {
+    const query = `INSERT INTO seed (filename) VALUES ($1)`;
+    return db.query(query, [ this.filename ]);
+  }
+
+  async applySeedData() {
+    if (await this.isApplied) {
+      console.log(`⚠️  Step: ${this.filename}, already applied.`);
+      return
+    }
+
+    console.log(`Seeding ${this.filename}:`);
+
+    const seedSteps = this.data.map(data => {
+      const { model, pk, fields } = data;
+      const columns = Object.keys(fields);
+      const values = Object.values(fields);
+      const parameterKeys = Array.from({length: values.length}, (v, k) => `$${k + 1}`);
+
+      const query = `INSERT INTO ${ model }
+        (${ columns.join(',') })
+        VALUES
+        (${ parameterKeys.join(',') })`;
+
+      return db.query(query, values)
+    });
+
+    const table = this.data[0].model;
+    return Promise.all(seedSteps)
+      .then(objects => console.log(`🌱 ${objects.length} object(s) applied to ${ table }.`))
+      .then(_ => this.commitStepToDb());
+  }
+}
+
+/**
+ * UTILS
+ */
+const readSeedFiles = () => {
+  const seedFolder = path.join(__base, "database/seeds/");
+  console.log(`Reading seeds from folder: ${seedFolder}\n`);
+
+  return fsPromises.readdir(seedFolder)
+    .then(files => files.map(filePath => {
+      const seedStep = new SeedStep(path.join(seedFolder, filePath));
+      seedStep.readData();
+      return seedStep;
+    }))
+    .catch(console.log)
+};
+
+const runAllSteps = (seedSteps) => {
+  return seedSteps.reduce(async (prevPromise, step) => {
+    await prevPromise;
+    return step.applySeedData();
+  }, Promise.resolve());
+
+  return Promise.all(promises);
+}
+
+/**
+ * Runner
+ */
+readSeedFiles()
+  .then(seedSteps => runAllSteps(seedSteps))
+  .finally(_ => process.exit(0));