Question 1

Why is this called "whitespace minify" instead of true minify?

Accepted Answer

True minify (what Terser, esbuild, SWC do) builds an AST, renames
variables to single letters, eliminates dead code, inlines
constants, hoists declarations, and applies dozens of other
transforms that can shrink code by 70-90%. All of those require a
full parser and are unsafe to do with regex tricks — get one edge
case wrong (a `with` block, a `Function` constructor, a `delete`
inside `eval`) and you ship broken JS. This tool is honest about
what it does: it strips comments and whitespace, which alone gets
you 40-70% on most code. The output is always semantically
identical to the input — no surprises. If you need the extra 30%,
run Terser locally.

Question 2

Should I use this in production?

Accepted Answer

For a small snippet (a one-file widget, an inline event handler, a
GTM custom HTML block) — yes, this is fine. For a real app's build
output — no, run Terser or esbuild in your build pipeline. They'll
shave another 20-40% via name mangling and dead-code elimination,
and they're already wired into Vite / webpack / Rollup / Parcel.
Think of this tool as "the moment you don't have a build pipeline":
someone pasted 300 lines in Slack, you want it 50% smaller before
inlining into an email or pasting into a CodePen demo.

Question 3

Does this break my code if it has template literals or regex?

Accepted Answer

No. The tokenizer treats template literals (`hello ${name}`),
regex literals (/abc/g), and string literals as opaque atomic
tokens — their internal whitespace and comments are preserved
byte-for-byte. The regex-vs-division disambiguator follows the
ECMA-262 rule (regex is allowed after an operator, keyword, or
punctuator that can't end an expression), which is the same logic
Acorn and Esprima use. So `let r = a / b; let s = /abc/g;` is
tokenized correctly even though both `/` characters look identical.
See the test suite — every regex / template-literal / regex-vs-
division case has a regression test.

Question 4

Why are name shortening / DCE missing?

Accepted Answer

They require a real parser that builds an AST, tracks scopes,
resolves bindings, and proves which code paths are dead. Doing
that correctly is roughly 8000-12000 lines of code (that's what
Terser and esbuild are). Shipping a 14kb tool that does it WRONG
would silently break user code in subtle ways (closures that
capture renamed vars, eval/with/Function that reference original
names, sourcemaps drift, etc). We'd rather be honest: use Terser
for that. The whitespace pass alone gets you 40-70%, which is the
biggest single win and the only one we can guarantee is safe.

Question 5

How is this different from running Terser locally?

Accepted Answer

Terser gives you ~30% more compression (variable name mangling +
DCE + property hoisting + constant folding), source maps, and
plugin support. Setup: `npm i -D terser` + a config file + a
build script. This tool gives you ~40-70% compression with zero
setup and zero risk of AST-level breakage. If you already have a
build pipeline, use Terser. If you don't (one-off snippet, GTM
tag, inline handler, pasted-in-Slack code), use this. The tools
serve different use cases — neither replaces the other.

JS Minifier — Compress JavaScript, Strip Comments & Whitespace

What this tool does

Tool details

How to use

1. Input

2. Process

3. Copy / Download

How JS Minifier fits into your work

Conversion jobs

Conversion checks

Good next steps

Real-world use cases

Inline a 14-line click handler into one HTML attribute

Shrink a pasted-in-Slack snippet before a CodePen demo

Compress a GTM custom HTML tag under the size budget

Squeeze a service-worker snippet without a bundler

Common pitfalls

Privacy

FAQ

Tool combos

JS Minifier — Compress JavaScript, Strip Comments & Whitespace

What this tool does

Tool details

How to use

1. Input

2. Process

3. Copy / Download

How JS Minifier fits into your work

Conversion jobs

Conversion checks

Good next steps

Real-world use cases

Inline a 14-line click handler into one HTML attribute

Shrink a pasted-in-Slack snippet before a CodePen demo

Compress a GTM custom HTML tag under the size budget

Squeeze a service-worker snippet without a bundler

Common pitfalls

Privacy

FAQ

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