Parcel v2.6.0; Lerna 5; processing Arrays non-destructively; managing local dependencies; converting libraries from Node.js to Deno

• Error overlay for React
• Support for source maps in Hot Module Reloading
• Locally scoped variables in CSS modules

• Outdated packages were updated.
• Support for Node.js v10 and v12 was deprecated.
• Publishing the Lerna repo locally was improved.

• Filtering an input Array to produce an output Array
• Mapping each input Array element to one output Array element
• Expanding each input Array element to zero or more output Array elements
• Filter-mapping (filtering and mapping in one step)
• Computing a summary for an Array
• Finding an Array element
• Checking a condition for all Array elements

They used Deno’s Node.js compatibility library and wrote a codemod to add the filename extension .ts to imports, change usages of global Node.js variables such as process and Buffer to Deno-specific imports, etc.