buildspec.yml

version: 0.2
env:
  variables:
    PORT: "2000"
    REACT_APP_ENV: "production"
    REACT_APP_TITLE: "My App"
    REACT_APP_FAVICON: "favicon.ico"
    REACT_APP_LOGO_TYPE: "vertical"
phases:
  install:
    on-failure: ABORT
    runtime-versions:
      nodejs: 14.x
    commands:
      - echo Install npm packages - START
      - npm i
      - echo Install npm packages - DONE
  build:
    commands:
      - echo Build ReactJS app - START
      - npm run build
      - echo Build ReactJS app - DONE
artifacts:
  files:
    - '**/*'
  base-directory: 'build'

sample buildspec.yml file to build reactjs app with aws code build