Changelog
v5.19.2
- fix performance hit from avoiding HTML comments in the output
v5.19.1
- Better avoid outputting
</script>
and HTML comments.
- Fix unused variables in class static blocks not being dropped correctly.
- Fix sourcemap names of methods that are
async
or static
v5.19.0
- Allow
/*@__MANGLE_PROP__*/
annotation in object.property
, in addition to property declarations.
v5.18.2
- Stop using recursion in hoisted defuns fix.
v5.18.1
- Fix major performance issue caused by hoisted defuns' scopes bugfix.
v5.18.0
- Add new
/*@__MANGLE_PROP__*/
annotation, to mark properties that should be mangled.
v5.17.7
- Update some dependencies
- Add consistent sorting for
v
RegExp flag
- Add
inert
DOM attribute to domprops
v5.17.6
- Fixes to mozilla AST input and output, for class properties, private properties and static blocks
- Fix outputting a shorthand property in quotes when safari10 and ecma=2015 options are enabled
configurable
and enumerable
, used in Object.defineProperty, added to domprops (#1393)
v5.17.5
- Take into account the non-deferred bits of a class, such as static properties, while dropping unused code.
v5.17.4
- Fix crash when trying to negate a class (
!class{}
)
- Avoid outputting comments between
yield
/await
and its argument
- Fix detection of left-hand-side of assignment, to avoid optimizing it like any other expression in some edge cases
v5.17.3
- Fix issue with trimming a static class property's contents accessing the class as
this
.
v5.17.2
- Be less conservative when detecting use-before-definition of
var
in hoisted functions.
- Support unusual (but perfectly valid) initializers of for-in and for-of loops.
- Fix issue where hoisted function would be dropped if it was after a
continue
statement
v5.17.1
- Fix evaluating
.length
when the source array might've been mutated
v5.17.0
- Drop vestigial
= undefined
default argument in IIFE calls (#1366)
- Evaluate known arrays'
.length
property when statically determinable
- Add
@__KEY__
annotation to mangle string literals (#1365)
v5.16.9
- Fix parentheses in output of optional chains (
a?.b
) (#1374)
- More documentation on source maps (#1368)
- New
lhs_constants
option, allowing to stop Terser from swapping comparison operands (#1361)
v5.16.8
- Become even less conservative around function definitions for
reduce_vars
- Fix parsing context of
import.meta
expressions such that method calls are allowed
v5.16.6
- Become less conservative with analyzing function definitions for
reduce_vars
- Parse
import.meta
as a real AST node and not an object.property
v5.16.5
- Correctly handle AST transform functions that mutate children arrays
- Don't mutate the options object passed to Terser (#1342)
- Do not treat BigInt like a number
v5.16.4
- Keep
(defaultArg = undefined) => ...
, because default args don't count for function length
- Prevent inlining variables into
?.
optional chains
- Avoid removing unused arguments while transforming
- Optimize iterating AST node lists
- Make sure
catch
and finally
aren't children of try
in the AST
- Use modern unicode property escapes (
\p{...}
) to parse identifiers when available
v5.16.3
- Ensure function definitions, don't assume the values of variables defined after them.
v5.16.2
- Fix sourcemaps with non-ascii characters (#1318)
- Support string module name and export * as (#1336)
- Do not move
let
out of for
initializers, as it can change scoping
- Fix a corner case that would generate the invalid syntax
if (something) let x
("let" in braceless if body)
- Knowledge of more native object properties (#1330)
- Got rid of Travis (#1323)
- Added semi-secret
asObject
sourcemap option to typescript defs (#1321)
v5.16.1
- Properly handle references in destructurings (
const { [reference]: val } = ...
)
- Allow parsing of
.#privatefield
in nested classes
- Do not evaluate operations that return large strings if that would make the output code larger
- Make
collapse_vars
handle block scope correctly
- Internal improvements: Typos (#1311), more tests, small-scale refactoring
v5.16.0
- Disallow private fields in object bodies (#1011)
- Parse
#privatefield in object
(#1279)
- Compress
#privatefield in object
v5.15.1
- Fixed missing parentheses around optional chains
- Avoid bare
let
or const
as the bodies of if
statements (#1253)
- Small internal fixes (#1271)
- Avoid inlining a class twice and creating two equivalent but
!==
classes.
v5.15.0
- Basic support for ES2022 class static initializer blocks.
- Add
AudioWorkletNode
constructor options to domprops list (#1230)
- Make identity function inliner not inline
id(...expandedArgs)
v5.14.2
- Security fix for RegExps that should not be evaluated (regexp DDOS)
- Source maps improvements (#1211)
- Performance improvements in long property access evaluation (#1213)
v5.14.1
- keep_numbers option added to TypeScript defs (#1208)
- Fixed parsing of nested template strings (#1204)
v5.14.0
- Switched to @jridgewell/source-map for sourcemap generation (#1190, #1181)
- Fixed source maps with non-terminated segments (#1106)
- Enabled typescript types to be imported from the package (#1194)
- Extra DOM props have been added (#1191)
- Delete the AST while generating code, as a means to save RAM
v5.13.1
- Removed self-assignments (
varname=varname
) (closes #1081)
- Separated inlining code (for inlining things into references, or removing IIFEs)
- Allow multiple identifiers with the same name in
var
destructuring (eg var { a, a } = x
) (#1176)
v5.13.0
- All calls to eval() were removed (#1171, #1184)
source-map
was updated to 0.8.0-beta.0 (#1164)
- NavigatorUAData was added to domprops to avoid property mangling (#1166)
v5.12.1
- Fixed an issue with function definitions inside blocks (#1155)
- Fixed parens of
new
in some situations (closes #1159)
v5.12.0
TERSER_DEBUG_DIR
environment variable
- @copyright comments are now preserved with the comments="some" option (#1153)
v5.11.0
- Unicode code point escapes (
\u{abcde}
) are not emitted inside RegExp literals anymore (#1147)
- acorn is now a regular dependency
v5.10.0
- Massive optimization to max_line_len (#1109)
- Basic support for import assertions
- Marked ES2022 Object.hasOwn as a pure function
- Fix
delete optional?.property
- New CI/CD pipeline with github actions (#1057)
- Fix reordering of switch branches (#1092), (#1084)
- Fix error when creating a class property called
get
- Acorn dependency is now an optional peerDependency
- Fix mangling collision with exported variables (#1072)
- Fix an issue with
return someVariable = (async () => { ... })()
(#1073)
v5.9.0
- Collapsing switch cases with the same bodies (even if they're not next to each other) (#1070).
- Fix evaluation of optional chain expressions (#1062)
- Fix mangling collision in ESM exports (#1063)
- Fix issue with mutating function objects after a second pass (#1047)
- Fix for inlining object spread
{ ...obj }
(#1071)
- Typescript typings fix (#1069)
v5.8.0
- Fixed shadowing variables while moving code in some cases (#1065)
- Stop mangling computed & quoted properties when keep_quoted is enabled.
- Fix for mangling private getter/setter and .#private access (#1060, #1068)
- Array.from has a new optimization when the unsafe option is set (#737)
- Mangle/propmangle let you generate your own identifiers through the nth_identifier option (#1061)
- More optimizations to switch statements (#1044)
v5.7.2
- Fixed issues with compressing functions defined in
global_defs
option (#1036)
- New recipe for using Terser in gulp was added to RECIPES.md (#1035)
- Fixed issues with
??
and ?.
(#1045)
- Future reserved words such as
package
no longer require you to disable strict mode to be used as names.
- Refactored huge compressor file into multiple more focused files.
- Avoided unparenthesized
in
operator in some for loops (it breaks parsing because of for..in loops)
- Improved documentation (#1021, #1025)
- More type definitions (#1021)
v5.7.1
- Avoided collapsing assignments together if it would place a chain assignment on the left hand side, which is invalid syntax (
a?.b = c
)
- Removed undefined from object expansions (
{ ...void 0 }
-> {}
)
- Fix crash when checking if something is nullish or undefined (#1009)
- Fixed comparison of private class properties (#1015)
- Minor performance improvements (#993)
- Fixed scope of function defs in strict mode (they are block scoped)
v5.7.0
- Several compile-time evaluation and inlining fixes
- Allow
reduce_funcs
to be disabled again.
- Add
spidermonkey
options to parse and format (#974)
- Accept
{get = "default val"}
and {set = "default val"}
in destructuring arguments.
- Change package.json export map to help require.resolve (#971)
- Improve docs
- Fix
export default
of an anonymous class with extends
v5.6.1
- Mark assignments to the
.prototype
of a class as pure
- Parenthesize
await
on the left of **
(while accepting legacy non-parenthesised input)
- Avoided outputting NUL bytes in optimized RegExps, to stop the output from breaking other tools
- Added
exports
to domprops (#939)
- Fixed a crash when spreading
...this
- Fixed the computed size of arrow functions, which improves their inlining
v5.6.0
- Added top-level await
- Beautify option has been removed in #895
- Private properties, getters and setters have been added in #913 and some more commits
- Docs improvements: #896, #903, #916
v5.5.1
- Fixed object properties with unicode surrogates on safari.
v5.5.0
- Fixed crash when inlining uninitialized variable into template string.
- The sourcemap for dist was removed for being too large.
v5.4.0
- Logical assignment
- Change
let x = undefined
to just let x
- Removed some optimizations for template strings, placing them behind
unsafe
options. Reason: adding strings is not equivalent to template strings, due to valueOf differences.
- The AST_Token class was slimmed down in order to use less memory.
v5.3.8
v5.3.7
Hotfix release, fixes package.json "engines" syntax
v5.3.6
- Fixed parentheses when outputting
??
mixed with ||
and &&
- Improved hygiene of the symbol generator
v5.3.5
- Avoid moving named functions into default exports.
- Enabled transform() for chain expressions. This allows AST transformers to reach inside chain expressions.
v5.3.4
- Fixed a crash when hoisting (with
hoist_vars
) a destructuring variable declaration
v5.3.3
source-map
library has been updated, bringing memory usage and CPU time improvements when reading input source maps (the SourceMapConsumer is now WASM based).
- The
wrap_func_args
option now also wraps arrow functions, as opposed to only function expressions.
v5.3.2
- Prevented spread operations from being expanded when the expanded array/object contains getters, setters, or array holes.
- Fixed very slow self-recursion in some cases of removing extraneous parentheses from
+
operations.
v5.3.1
- An issue with destructuring declarations when
pure_getters
is enabled has been fixed
- Fixed a crash when chain expressions need to be shallowly compared
- Made inlining functions more conservative to make sure a function that contains a reference to itself isn't moved into a place that can create multiple instances of itself.
v5.3.0
- Fixed a crash when compressing object spreads in some cases
- Fixed compiletime evaluation of optional chains (caused typeof a?.b to always return "object")
- domprops has been updated to contain every single possible prop
v5.2.1
- The parse step now doesn't accept an
ecma
option, so that all ES code is accepted.
- Optional dotted chains now accept keywords, just like dotted expressions (
foo?.default
)
v5.2.0
- Optional chaining syntax is now supported.
- Consecutive await expressions don't have unnecessary parens
- Taking the variable name's length (after mangling) into consideration when deciding to inline
v5.1.0
import.meta
is now supported
- Typescript typings have been improved
v5.0.0
in
operator now taken into account during property mangle.
- Fixed infinite loop in face of a reference loop in some situations.
- Kept exports and imports around even if there's something which will throw before them.
- The main exported bundle for commonjs, dist/bundle.min.js is no longer minified.
v5.0.0-beta.0
- BREAKING:
minify()
is now async and rejects a promise instead of returning an error.
- BREAKING: Internal AST is no longer exposed, so that it can be improved without releasing breaking changes.
- BREAKING: Lowest supported node version is 10
- BREAKING: There are no more warnings being emitted
- Module is now distributed as a dual package - You can
import
and require()
too.
- Inline improvements were made
v4.8.1 (backport)
- Security fix for RegExps that should not be evaluated (regexp DDOS)
v4.8.0
- Support for numeric separators (
million = 1_000_000
) was added.
- Assigning properties to a class is now assumed to be pure.
- Fixed bug where
yield
wasn't considered a valid property key in generators.
v4.7.0
- A bug was fixed where an arrow function would have the wrong size
arguments
object is now considered safe to retrieve properties from (useful for length
, or 0
) even when pure_getters
is not set.
- Fixed erroneous
const
declarations without value (which is invalid) in some corner cases when using collapse_vars
.
v4.6.13
- Fixed issue where ES5 object properties were being turned into ES6 object properties due to more lax unicode rules.
- Fixed parsing of BigInt with lowercase
e
in them.
v4.6.12
- Fixed subtree comparison code, making it see that
[1,[2, 3]]
is different from [1, 2, [3]]
- Printing of unicode identifiers has been improved
v4.6.11
- Read unused classes' properties and method keys, to figure out if they use other variables.
- Prevent inlining into block scopes when there are name collisions
- Functions are no longer inlined into parameter defaults, because they live in their own special scope.
- When inlining identity functions, take into account the fact they may be used to drop
this
in function calls.
- Nullish coalescing operator (
x ?? y
), plus basic optimization for it.
- Template literals in binary expressions such as
+
have been further optimized
v4.6.10
- Do not use reduce_vars when classes are present
v4.6.9
- Check if block scopes actually exist in blocks
v4.6.8
- Take into account "executed bits" of classes like static properties or computed keys, when checking if a class evaluation might throw or have side effects.
v4.6.7
- Some new performance gains through a
AST_Node.size()
method which measures a node's source code length without printing it to a string first.
- An issue with setting
--comments
to false
in the CLI has been fixed.
- Fixed some issues with inlining
unsafe_symbols
compress option was added, which turns Symbol("name")
into just Symbol()
- Brought back compress performance improvement through the
AST_Node.equivalent_to(other)
method (which was reverted in v4.6.6).
v4.6.6
(hotfix release)
- Reverted code to 4.6.4 to allow for more time to investigate an issue.
v4.6.5 (REVERTED)
- Improved compress performance through using a new method to see if two nodes are equivalent, instead of printing them to a string.
v4.6.4
- The
"some"
value in the comments
output option now preserves @lic
and other important comments when using //
</script>
is now better escaped in regex, and in comments, when using the inline_script
output option
- Fixed an issue when transforming
new RegExp
into /.../
when slashes are included in the source
AST_Node.prototype.constructor
now exists, allowing for easier debugging of crashes
- Multiple if statements with the same consequents are now collapsed
- Typescript typings improvements
- Optimizations while looking for surrogate pairs in strings
v4.6.3
- Annotations such as
/*#__NOINLINE__*/
and /*#__PURE__*/
may now be preserved using the preserve_annotations
output option
- A TypeScript definition update for the
keep_quoted
output option.
v4.6.2
- A bug where functions were inlined into other functions with scope conflicts has been fixed.
/*#__NOINLINE__*/
annotation fixed for more use cases where inlining happens.
v4.6.1
- Fixed an issue where a class is duplicated by reduce_vars when there's a recursive reference to the class.
v4.6.0
- Fixed issues with recursive class references.
- BigInt evaluation has been prevented, stopping Terser from evaluating BigInts like it would do regular numbers.
- Class property support has been added
v4.5.1
(hotfix release)
- Fixed issue where
() => ({})[something]
was not parenthesised correctly.
v4.5.0
- Inlining has been improved
- An issue where keep_fnames combined with functions declared through variables was causing name shadowing has been fixed
- You can now set the ES version through their year
- The output option
keep_numbers
has been added, which prevents Terser from turning 1000
into 1e3
and such
- Internal small optimisations and refactors
v4.4.3
- Number and BigInt parsing has been fixed
/*#__INLINE__*/
annotation fixed for arrow functions with non-block bodies.
- Functional tests have been added, using this repository.
- A memory leak, where the entire AST lives on after compression, has been plugged.
v4.4.2
- Fixed a problem with inlining identity functions
v4.4.1
note: This introduced a feature, therefore it should have been a minor release.
- Fixed a crash when
unsafe
was enabled.
- An issue has been fixed where
let
statements might be collapsed out of their scope.
- Some error messages have been improved by adding quotes around variable names.
v4.4.0
- Added
/*#__INLINE__*/
and /*#__NOINLINE__*/
annotations for calls. If a call has one of these, it either forces or forbids inlining.
v4.3.11
- Fixed a problem where
window
was considered safe to access, even though there are situations where it isn't (Node.js, workers...)
- Fixed an error where
++
and --
were considered side-effect free
Number(x)
now needs both unsafe
and and unsafe_math
to be compressed into +x
because x
might be a BigInt
keep_fnames
now correctly supports regexes when the function is in a variable declaration
v4.3.10
- Fixed syntax error when repeated semicolons were encountered in classes
- Fixed invalid output caused by the creation of empty sequences internally
- Scopes are now updated when scopes are inlined into them
v4.3.9
- Fixed issue with mangle's
keep_fnames
option, introduced when adding code to keep variable names of anonymous functions
v4.3.8
v4.3.7
- Parsing of regex options in the CLI (which broke in v4.3.5) was fixed.
- typescript definition updates
v4.3.6
(crash hotfix)
v4.3.5
- Fixed an issue with DOS line endings strings separated by
\
and a new line.
- Improved fix for the output size regression related to unused references within the extends section of a class.
- Variable names of anonymous functions (eg:
const x = () => { ... }
or var func = function () {...}
) are now preserved when keep_fnames is true.
- Fixed performance degradation introduced for large payloads in v4.2.0
v4.3.4
- Fixed a regression where the output size was increased when unused classes were referred to in the extends clause of a class.
- Small typescript typings fixes.
- Comments with
@preserve
, @license
, @cc_on
as well as comments starting with /*!
and /**!
are now preserved by default.
v4.3.3
- Fixed a problem where parsing template strings would mix up octal notation and a slash followed by a zero representing a null character.
- Started accepting the name
async
in destructuring arguments with default value.
- Now Terser takes into account side effects inside class
extends
clauses.
- Added parens whenever there's a comment between a return statement and the returned value, to prevent issues with ASI.
- Stopped using raw RegExp objects, since the spec is going to continue to evolve. This ensures Terser is able to process new, unknown RegExp flags and features. This is a breaking change in the AST node AST_RegExp.
v4.3.2
- Typescript typing fix
- Ensure that functions can't be inlined, by reduce_vars, into places where they're accessing variables with the same name, but from somewhere else.
v4.3.1
- Fixed an issue from 4.3.0 where any block scope within a for loop erroneously had its parent set to the function scopee
- Fixed an issue where compressing IIFEs with argument expansions would result in some parameters becoming undefined
- addEventListener options argument's properties are now part of the DOM properties list.
v4.3.0
- Do not drop computed object keys with side effects
- Functions passed to other functions in calls are now wrapped in parentheses by default, which speeds up loading most modules
- Objects with computed properties are now less likely to be hoisted
- Speed and memory efficiency optimizations
- Fixed scoping issues with
try
and switch
v4.2.1
- Minor refactors
- Fixed a bug similar to #369 in collapse_vars
- Functions can no longer be inlined into a place where they're going to be compared with themselves.
- reduce_funcs option is now legacy, as using reduce_vars without reduce_funcs caused some weird corner cases. As a result, it is now implied in reduce_vars and can't be turned off without turning off reduce_vars.
- Bug which would cause a random stack overflow has now been fixed.
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
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
v3.16.1
- Fixed issue where Terser being imported with
import
would cause it not to work due to the __esModule
property. (PR #254 was submitted, which was nice, but since it wasn't a pure commonJS approach I decided to go with my own solution)
v3.16.0
- No longer leaves names like Array or Object or window as a SimpleStatement (statement which is just a single expression).
- Add support for sections sourcemaps (IndexedSourceMapConsumer)
- Drops node.js v4 and starts using commonJS
- Is now built with rollup
v3.15.0
- Inlined spread syntax (
[...[1, 2, 3], 4, 5] => [1, 2, 3, 4, 5]
) in arrays and objects.
- Fixed typo in compressor warning
- Fixed inline source map input bug
- Fixed parsing of template literals with unnecessary escapes (Like
\\a
)