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Leo Esaki, JavaScript Developer in Tokyo, Japan
Leo Esaki

JavaScript Developer in Tokyo, Japan

Member since September 7, 2017
Leo is a talented and passionate full-stack developer with a focus on front-end development with React.js. He is also specialized in web and service-oriented applications and dynamic languages such as JavaScript, Ruby, PHP, Python, etc. Leo is passionate about working with motivated teams and getting things done. Currently, he prefers to work with React.js and Redux. He strictly adheres to the DRY principle and KISS approach.
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Portfolio

Experience

  • JavaScript, 10 years
  • Ruby on Rails (RoR), 7 years
  • Angular, 6 years
  • React, 6 years
  • Python, 6 years
  • Django, 6 years
  • Redux, 4 years
  • ECMAScript (ES6), 3 years
Tokyo, Japan

Availability

Full-time

Preferred Environment

Ubuntu, Mac, Git, Sublime Text, Atom, PyCharm

The most amazing...

...project I worked on is a Fintech platform that provides a portfolio management solution with intuitive dashboards and console for both clients and advisors.

Employment

  • Full-stack Developer

    2018 - 2018
    Open Polytechnic of New Zeland (via Toptal)
    • Refactored old AngularJS learner's dashboard page into Angular 5.
    • Implemented proof-of-concept feature for learners to set custom course start and end date.
    • Refactored old integration tests written in mocha into WDIO (WebDriverIO) tests so that multiple tests can be run simultaneously.
    • Worked on portfolio (course model structure) migration and refactored the related API endpoints.
    • Ensured multiple reviewers can be added to the courses.
    Technologies: Angular 5, AngularJS, Node, Express, WDIO, Grunt, TypeScript, Mocha

  • Full-stack Python Developer

    2018 - 2018
    S3: Shapiro Settlement Solutions (via Toptal)
    • Re-implemented data extraction from Excel file into various microservices databases based on their new `ETL workflow.
    • Updated database models definition in Cloud Datastore which is used in the new extraction flow.
    • Implemented transformation of imported column data through front-end UI in React.
    • Refactored back-end APIs for preloading of entity and relationship options in Python.
    • Implemented UI and back-end APIs for mapping relationships between entities imported from Excel files.
    Technologies: Python, Microservice, Google App Engine, Google Cloud Datastore, React, Redux, GraphQL, StoryBook, Flask

  • Front-end Web Developer

    2018 - 2018
    Megawarne Consulting (via Toptal)
    • Implemented new UI layout with Ant Design.
    • Refactored authentication logic with redux-auth-wrapper.
    • Implemented Web socket communication between back-end and front-end through MsgPack - binary serialization format.
    • Implemented showing of field level validation error message from the backend api response with redux-form and promise handling.
    • Tested and demonstrated React components using Storybook.
    • Introduced the HOCs for code reuse, logic and bootstrap abstraction.
    • Implemented live detection view through web socket subscription.
    Technologies: React.js, Redux, Web Socket, MsgPack, Redux-Form, Ant Design, Storybook, Java, Maven, Vagrant, Virtual Box, Postgres

  • Sr. UI Developer

    2017 - 2017
    OpenRisk Technologies LLC (via Toptal)
    • Implemented Kafka topics UI into the React.js/Redux web app to handle real-time data feeds.
    • Created multi-dimensional stocks chart with AmChart.
    • Implemented complex diagram visualization and interaction with Ogma.
    • Tested and demonstrated React components using Storybook.
    • Refactored authentication logic with redux-auth-wrapper.
    • Utilized Immutable.js with PureComponent to boost the performance.
    Technologies: React.js, Redux, Redux-Saga, Immutable.js, AmCharts, HighCharts, D3, RxJS, Material UI, Storybook, Kafka, Ogma

  • Full-stack Web Developer

    2016 - 2017
    BetaSmartz
    • Implemented RESTful APIs for client on-boarding path.
    • Improved advisor console to send invitation to new clients.
    • Expanded firm's console with Application manager and AcquireSmartz.
    • Contributed to the front-end implementation of on-boarding UI.
    • Updated the UI and flow logic for creating new accounts and new goals.
    Technologies: React.js, Redux, Redux-Saga, Immutable.js, Jest, Python, Django, Jenkins, Bitbucket, Jira, Stripe API, Quovo API, Plaid API, pandas, Numpy

  • Full-stack developer

    2016 - 2016
    Mosaic Sustainability
    • Built a custom CMS to manage micro sites, pages, groups and users.
    • Developed RESTful APIs to connect tableau server and get response data.
    • Implemented the view of tableaus with user-specific settings.
    • Built front-end with Angular 2.
    Technologies: Ruby on Rails, Angular, Github, Tableau

  • Full-stack Web Developer

    2015 - 2016
    Theme Paradise
    • Worked on part-time engagment for building of several responsive multi-purpose WordPress themes.
    • Built my own WordPress theme framework called Crystal.
    • Strong experience with building WordPress shortcodes along with Visual Composer.
    Technologies: PHP, WordPress, Javascript, jQuery

  • Web Developer

    2015 - 2016
    Nelou
    • Built a RESTful API for web and mobile app.
    • Developed cross-browser compliant front-end using AngularJS.
    • Tested front-end using Jasmine and back-end using Mocha.
    • Implemented an integration with Stripe for card payment processing.
    • Identified and corrected software deficiencies.
    Technologies: Ruby on Rails, Angular, Bitbucket, Mocha, Git

  • Full-stack Web Developer

    2015 - 2015
    Charibin
    • Developed a fundraising auction system with Meteor.js.
    • Improved UI and UX with Bootstrap based on the mockup provided.
    • Revamped project setup and deployment with iron-cli and mupx.
    • Built a module to cache the backend API responses in the front-end to improve performance.
    • Conducted technical and functional research and analysis.
    Technologies: Meteor.js, Stripe, Bootstrap, Iron-cli, Google Places API, GuideStar

  • Web Developer

    2012 - 2014
    Manglobe, Inc.
    • Worked as a internal developer to maintain and upgrade the web app for their internal management system.
    • Scripted in Python and Shell for system administration and data processing.
    • Led a team of developers implementing business applications on top of the in-house developed RAD tool.
    • Designed and built a real-time chat module.
    • Implemented a continuous integration and deployment process.
    • Improved development and testing workflow with virtualization and container technologies.
    Technologies: Ruby on Rails, Python

Experience

  • BetaSmartz Web App Development (Development)
    https://www.betasmartz.com

    - Implemented RESTful APIs for client on-boarding path.
    - Improved advisor console to send invitation to new clients.
    - Expanded firm's console with Application manager and AcquireSmartz.
    - Contributed to the front-end implementation of on-boarding UI.
    - Updated the UI & flow logic for creating new accounts and new goals.

  • Mosaic Tableau Management (Development)

    - Built a custom CMS to manage micro sites, pages, groups and users.
    - Developed RESTful APIs to connect tableau server and get response data.
    - Implemented the view of tableaus with user-specific settings.
    - Built front-end with Angular 2.

  • Nelou CMS (Development)

    - Developed a RESTful API for web & mobile app.
    - Developed front-end using AngularJS.
    - Tested front-end using Jasmine and back-end using Mocha.
    - Implemented an integration with Stripe for card payment processing.
    - Identified and corrected software deficiencies.

Skills

  • Languages

    CSS3, SQL, JavaScript, C++, C, Sass, HTML5, Python, PHP, ECMAScript (ES6), Java, GraphQL

  • Frameworks

    Laravel, Redux, Django, Angular, Koa, Express.js, Ruby on Rails (RoR)

  • Libraries/APIs

    React Redux, Ramda, Lodash, Redux-saga, Redux Form, D3.js, jQuery, React, Node.js, PayPal API

  • Tools

    GitHub, Bitbucket, Redux Thunk, Webpack, Sublime Text 3, Slack

  • Paradigms

    Object-oriented Programming (OOP), Functional Programming, REST, Continuous Integration (CI)

  • Platforms

    WordPress, Ubuntu, Windows, Mac

  • Storage

    MySQL, MongoDB, SQLite, PostgreSQL, Redis

  • Other

    SSH

Education

  • Bachelor's degree in Computer Engineering
    2008 - 2012
    Tokyo University of Science - Tokyo, Japan
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