Darold is available for hire

Darold So

Verified Expert in Engineering

Software Developer

Fukuoka, Japan

Toptal member since March 26, 2021

Expertise

Front-end User Interface (UI)Web Development Full-stack Development HTML5 JavaScript CSS React ECMAScript (ES6)Back-end Git Apache Click Twitter Bootstrap

Bio

Darold is a problem solver who can consistently devise scalable and sustainable solutions. He had worked for a major bank, an IT consultancy firm, and different startups. Darold is good at prototyping MVP, setting up front-end architecture, developing interactive applications, and refactoring legacy codebases.

Portfolio

LINE Fukuoka

JavaScript, Java, HTML, CSS, Vue, Vuex, React, Docker, Cypress, E2E Testing...

POPBO Net Limited

JavaScript, React, React Native, Magento 2, Redux, Redux-Saga, Git...

HSBC Hong Kong

JavaScript, React, Storybook, Git, CSS, Redux, ECMAScript (ES6), Node.js, CSS3...

Experience

JavaScript - 8 years React - 4 years Vue - 3 years Tailwind CSS - 3 years Next.js - 3 years React Native - 2 years Node.js - 2 years TypeScript - 1 year

Availability

Part-time

Preferred Environment

Git, MacOS, Sublime Text 3, iTerm2, Visual Studio Code (VS Code)

The most amazing...

...project I've worked on is a React Native property listing app that shows VR, videos, and photos of the property. It then selects properties to compare metrics.

Work Experience

Front-end Engineer

2022 - 2023

LINE Fukuoka

Migrated the front end of the LINE Store from Java Thymeleaf templates with Vanilla JS to Vue 3 (composition API) single-page application.
Developed new features/campaign sites for the LINE Store.
Improved the performance, accessibility, and SEO of the LINE Store based on the Lighthouse metrics.
Created end-to-end test suites with Cypress to ensure nothing breaks during version upgrades.

Technologies: JavaScript, Java, HTML, CSS, Vue, Vuex, React, Docker, Cypress, E2E Testing, Tailwind CSS, Responsive Web Design (RWD), Front-end Development, JSX, Pixel Perfect, Next.js, HTML5

Senior Software Engineer

2019 - 2022

POPBO Net Limited

Developed real estate listing iOS and Android apps with React Native that allow users to browse realty photos, videos, and 3D scenes on a single screen.
Set up multiple build schemes and build types to version two separate apps with different icons and assets using a single codebase.
Developed an internal CMS that serves testing data via REST API with Node.js, Express.js, and MongoDB.
Maintained and updated eCommerce platforms built with Magento.

Technologies: JavaScript, React, React Native, Magento 2, Redux, Redux-Saga, Git, ECMAScript (ES6), Xcode, Android Studio, Node.js, CSS, HTML, iTerm2, Front-end, GitHub, Webpack, Tailwind CSS, REST APIs, Figma, Visual Studio Code (VS Code), GraphQL, TypeScript, Web Development, User Interface (UI), Responsive UI, APIs, API Integration, iOS, Android, Expo, Firebase, UI Components, Material UI, Storybook, Jest, Full-stack, Back-end, MERN Stack, PHP, MongoDB, Responsive Web Design (RWD), Front-end Development, Full-stack Development, JSX, Pixel Perfect, Next.js, HTML5

Development Specialist

2018 - 2019

HSBC Hong Kong

Managed a team of 10+ developers in China to revamp the user interface of the banking portal using React and Redux.
Performed code reviews as well as hands-on coding to enhance the existing React components library, including refactoring, adding new props, and splitting components, which will be shared across independent projects.
Coordinated React version upgrade of 10+ repositories from version 15 to version 16.
Set up JavaScript coding standards, best practices, and ESLint rules extending on Airbnb preset.
Trained other team members on React and front-end knowledge.

Technologies: JavaScript, React, Storybook, Git, CSS, Redux, ECMAScript (ES6), Node.js, CSS3, HTML, iTerm2, Front-end, GitHub, Webpack, Gatsby, REST APIs, Web Development, User Interface (UI), Responsive UI, APIs, API Integration, UI Components, Responsive Web Design (RWD), Front-end Development, JSX, Pixel Perfect, HTML5

Staff Software Engineer

2017 - 2018

M800

Revamped the company website as the lead developer in a team of three with isomorphic React, using Next.js as a server-rendering framework.
Adopted utility-first CSS approach using Bootstrap 3 before TailwindCSS became popular. Combined it with React components to create flexible and highly reusable components.
Enhanced company internal React component libraries by refactoring and extending existing components.

Technologies: JavaScript, React, ECMAScript (ES6), Redux, Bootstrap 3, Next.js, Node.js, CSS, HTML, Git, iTerm2, Front-end, Webpack, Bootstrap, REST APIs, Web Development, User Interface (UI), Responsive UI, APIs, API Integration, UI Components, Full-stack, Responsive Web Design (RWD), Front-end Development, Full-stack Development, JSX, Pixel Perfect, HTML5

Senior Front-end Developer

2017 - 2017

LavaMap

Implemented Braintree payment gateway using JavaScript and PHP SDK to support monthly and annual subscriptions with arbitrary prices where customers can cancel the subscription and get a refund.
Refactored the existing codebase, including several controller files with more than 10,000 lines of code (LOC).
Developed new core features, including a smart filter list for US properties, server-side export CSV for properties, contacts with different layouts, and enhanced property tagging from one-to-one to many-to-many.

Technologies: JavaScript, AngularJS, Git, AWS Elastic Beanstalk, Braintree SDK, Amazon Web Services (AWS), PostgreSQL, CSS, HTML, iTerm2, Front-end, GitHub, REST APIs, Web Development, User Interface (UI), Responsive UI, Angular, UI Components, Back-end, Stripe, PHP, Responsive Web Design (RWD), Front-end Development, Pixel Perfect, Mapbox, HTML5

Senior Front-end Developer

2016 - 2017

MoneyHero.com.hk 4

Implemented the front end of the user login feature using the existing AngularJS components library.
Refactored the components library and added new components.
Integrated with Amazon Cognito and API Gateway to preserve user data in the AWS cloud.

Technologies: JavaScript, iTerm2, Git, AngularJS, CSS, Amazon Cognito, Amazon API Gateway, Amazon Web Services (AWS), HTML, Front-end, GitHub, REST APIs, Web Development, Responsive UI, APIs, API Integration, Angular, UI Components, Material UI, Responsive Web Design (RWD), Front-end Development, Pixel Perfect, HTML5

Software Engineer

2015 - 2016

Jobable

Developed an employer and candidate portal from scratch in test-driven approach. Built RESTful API back end with Symfony and SPA front end using AngularJS.
Developed the job search website jobable.com. The back end was built with Node.js and the front end with Jade, Sass, and ES6.
Fixed and enhanced an unfinished version of the employer and candidate portal built with CodeIgniter. Communicated with a database designer to implement the complete flow of job posting and applications.

Technologies: JavaScript, AngularJS, Node.js, ECMAScript (ES6), CSS, HTML, Git, Front-end, GitHub, Bootstrap, Bootstrap 3, REST APIs, Web Development, Responsive UI, APIs, API Integration, UI Components, Full-stack, Back-end, PHP, Responsive Web Design (RWD), Front-end Development, Full-stack Development, Pixel Perfect, HTML5

Freelance Developer

2015 - 2016

Self-employed

Developed a membership management system for the Hong Kong Rowing Association with Laravel as the back end and Vue.js (v1.0.28) as the front end.
Developed the website of the Hong Kong Rowing Association using WordPress. Created a theme for the presentation and a plugin for the data logic of the website.
Developed a series of interactive exercises for an e-book for a local publisher. Built the front end using Vue.js (v0.12).

Technologies: JavaScript, Laravel, Vue, WordPress, Amazon Web Services (AWS), Amazon S3 (AWS S3), Amazon EC2, PHP, CSS, HTML, Git, iTerm2, Front-end, GitHub, Bootstrap, Bootstrap 3, Web Development, Responsive UI, APIs, API Integration, iOS, Android, Expo, Full-stack, Back-end, Responsive Web Design (RWD), Front-end Development, Full-stack Development, HTML5

Web Developer

2012 - 2015

InMart Resources

Developed interactive and responsive websites for corporations, shopping malls using HTML, CSS, JavaScript, jQuery, and Drupal.
Built the front end of a web application and back-end controllers using Yii.
Created an eCommerce website for a local jewelry shop with PrestaShop as the sole developer.

Technologies: JavaScript, CSS, HTML, jQuery, Yii 2, Drupal 7, MySQL, CSS3, PHP, Front-end, Bootstrap, Bootstrap 3, Web Development, Responsive UI, Angular, Full-stack, WordPress, Back-end, Responsive Web Design (RWD), Front-end Development, Full-stack Development, Drupal, HTML5

Experience

Bisu App

https://www.loom.com/share/555f8085f776419cb6c5745c18fc46c6?sid=70ec2299-0dd5-4b5a-bced-9532b98e7722

A Japan-based health tracking app built with React Native. I was the major developer of the mobile application to develop the interactive data visualization, user personalization questionnaire, and personal health report, which was generated based on user data and specific algorithms.

Property Listing App

A Hong Kong-based app for real estate property listing built with React Native. I was the lead app developer to develop the property detail screen, which displays the VR view, videos, and photos of the property, as well as the property comparison screen, which can compare up to five properties interactively.

LINE Web Store

https://store.line.me/en

The online store for the most popular messenger app in Japan. I am the lead front-end engineer and liaised with the back-end developers, planners, and automation testers to design, develop, test and release new features without downtime.

Bisu Website

I took over the front-end implementation when the website was 80% done with heavy animation performance issues, which resulted in dropped frame rates. I improved website animation performance using a modern CSS approach and restored rendering performance to 60 FPS. I also fixed the mobile layout to make sure the animation is smooth and looks great on smaller screens.

React Native Comparison Table

https://github.com/daroldso/react-native-comparison-table

Developed a comparison table component with a fixed header for React Native. Users may scroll vertically or horizontally to browse the data of subjects with frozen header rows and columns. The component can be used in a declarative approach and define the content for each table row individually.

jQuery Full-page Image Zoom

https://github.com/daroldso/fpimagezoom

A jQuery plugin that enables full-page zooming when users click on the image. Upon image zooming, users can scroll the image with a mouse move and dismiss zooming on click. The plugin was created for a fashion eCommerce website to display fashion items.

HTML5 Educational Game

https://github.com/daroldso/edcity-ebook

An in-app web-based HTML5 educational game built with Vue. The project was built when AngularJS was losing traction due to performance issues, and React was not a popular choice. After evaluating framework choices, I picked Vue, despite still being in the pre-release stage, for its Angular-like syntax and component-based architecture.

There are 10 chapters with a total of 35 exercises. The exercises include multiple choices, true or false, drag and drop, and line matching tasks.

Education

2005 - 2008

Bachelor's Degree in Digital Graphic Communication

Hong Kong Baptist University - Hong Kong

Skills

Libraries/APIs

React, Node.js, jQuery, REST APIs, Lodash, Vue, Redux-Saga, Vuex, Stripe, Highcharts

Tools

Sublime Text 3, JSX, Git, GitHub, Expo, Photoshop CS5, Amazon Cognito, Braintree SDK, Xcode, Android Studio, Webpack, Figma

Languages

JavaScript, CSS, ECMAScript (ES6), HTML, CSS3, HTML5, PHP, GraphQL, TypeScript, Java

Frameworks

React Native, Redux, Bootstrap 3, Next.js, Tailwind CSS, Bootstrap, Material UI, AngularJS, Laravel, Yii 2, Angular, Jest, Cypress, Thymeleaf

Paradigms

Responsive Web Design (RWD), E2E Testing

Platforms

MacOS, Magento 2, WordPress, Drupal 7, AWS Elastic Beanstalk, Amazon Web Services (AWS), Amazon EC2, Visual Studio Code (VS Code), iOS, Android, Firebase, Docker, Drupal, Mapbox

Storage

MySQL, PostgreSQL, Amazon S3 (AWS S3), MongoDB

Other

Front-end, Web Development, User Interface (UI), Responsive UI, UI Components, Front-end Development, Full-stack Development, Pixel Perfect, iTerm2, APIs, API Integration, Full-stack, Back-end, Storybook, Amazon API Gateway, Gatsby, MERN Stack, Web UX

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