v4.2.0

• When the source map URL is inline, don't write it to a file.
• Fixed output parens when a lambda literal is the tag on a tagged template string.
• The mangle.properties.undeclared option was added. This enables the property mangler to mangle properties of variables which can be found in the name cache, but whose properties are not known to this Terser run.
• The v8 bug where the toString and source representations of regexes like RegExp("\\\n") includes an actual newline is now fixed.
• Now we're guaranteed to not have duplicate comments in the output
• Domprops updates

v4.1.4

• Fixed a crash when inlining a function into somewhere else when it has interdependent, non-removable variables.

v4.1.3

• Several issues with the reduce_vars option were fixed.
• Starting this version, we only have a dist/bundle.min.js

v4.1.2

• The hotfix was hotfixed

v4.1.1

• Fixed a bug where toplevel scopes were being mixed up with lambda scopes

v4.1.0

• Internal functions were replaced by Object.assign, Array.prototype.some, Array.prototype.find and Array.prototype.every.
• A serious issue where some ESM-native code was broken was fixed.
• Performance improvements were made.
• Support for BigInt was added.
• Inline efficiency was improved. Functions are now being inlined more proactively instead of being inlined only after another Compressor pass.

v4.0.2

(Hotfix release. Reverts unmapped segments PR #342, which will be put back on Terser when the upstream issue is resolved)

v4.0.1

• Collisions between the arguments of inlined functions and names in the outer scope are now being avoided while inlining
• Unmapped segments are now preserved when compressing a file which has source maps
• Default values of functions are now correctly converted from Mozilla AST to Terser AST
• JSON ⊂ ECMAScript spec (if you don't know what this is you don't need to)
• Export AST_* classes to library users
• Fixed issue with collapse_vars when functions are created with the same name as a variable which already exists
• Added MutationObserverInit (Object with options for initialising a mutation observer) properties to the DOM property list
• Custom Error subclasses are now internally used instead of old-school Error inheritance hacks.
• Documentation fixes
• Performance optimizations

v4.0.0

• breaking change: The variables property of all scopes has become a standard JavaScript Map as opposed to the old bespoke Dictionary object.
• Typescript definitions were fixed
• terser --help was fixed
• The public interface was cleaned up
• Fixed optimisation of Array and new Array
• Added the keep_quoted=strict mode to mangle_props, which behaves more like Google Closure Compiler by mangling all unquoted property names, instead of reserving quoted property names automatically.
• Fixed parent functions' parameters being shadowed in some cases
• Allowed Terser to run in a situation where there are custom functions attached to Object.prototype
• And more bug fixes, optimisations and internal changes

v3.17.0

• More DOM properties added to --mangle-properties's DOM property list
• Closed issue where if 2 functions had the same argument name, Terser would not inline them together properly
• Fixed issue with hasOwnProperty.call
• You can now list files to minify in a Terser config file
• Started replacing new Array(<number>) with an array literal
• Started using ES6 capabilities like Set and the includes method for strings and arrays