utils: api feature + app error + catch async errors

Author: krishpranav

utils/api_feature.js

@@ -0,0 +1,66 @@
+export class ApiFeatures {
+    constructor(mongooseQuery, queryString) {
+        this.mongooseQuery = mongooseQuery;
+        this.queryString = queryString;
+    }
+
+    pagination() {
+        const PAGE_LIMIT = 3;
+        let PAGE_NUMBER = this.queryString.page * 1 || 1;
+        if (this.queryString.page <= 0) PAGE_NUMBER = 1;
+        const PAGE_SKIP = (PAGE_NUMBER - 1) * PAGE_LIMIT;
+
+        this.mongooseQuery.skip(PAGE_SKIP).limit(PAGE_LIMIT);
+        return this;
+    }
+
+    filteration() {
+        let filterObj = { ...this.queryString };
+
+        let excludedQuery = ["page", "sort", "fields", "keyword"];
+
+        excludedQuery.forEach((ele) => {
+            delete filterObj[ele];
+        });
+        filterObj = JSON.stringify(filterObj);
+
+        filterObj = filterObj.replace(
+            /\b(gt|gte|lt|lte)\b/g,
+            (match) => `$${match}`
+        );
+        filterObj = JSON.parse(filterObj);
+
+        this.mongooseQuery.find(filterObj);
+        return this;
+    }
+
+    sort() {
+        if (this.queryString.sort) {
+            let sortedBy = this.queryString.sort.split(",").join(" ");
+            this.mongooseQuery.sort(sortedBy);
+        }
+        return this;
+    }
+
+    search() {
+        if (this.queryString.keyword) {
+
+            this.mongooseQuery.find({
+                $or: [
+                    { title: { $regex: this.queryString.keyword, $options: "i" } },
+                    { descripton: { $regex: this.queryString.keyword, $options: "i" } },
+                ],
+            });
+        }
+        return this;
+    }
+
+
+    fields() {
+        if (this.queryString.fields) {
+            let fields = this.queryString.fields.split(",").join(" ");
+            console.log(fields);
+        }
+        return this;
+    }
+}

utils/app_error.js

@@ -0,0 +1,6 @@
+export class AppError extends Error {
+    constructor(message, statuscode) {
+        super(message);
+        this.statuscode = statuscode;
+    }
+}

utils/catch_async_error.js

@@ -0,0 +1,5 @@
+export let catchAsyncError = (fn) => {
+    return (req, res, next) => {
+        fn(req, res, next).catch((err) => next(err));
+    };
+};