[Pkg-javascript-commits] [uglifyjs] 87/491: document minify() option `toplevel` (#1979)
Jonas Smedegaard
dr at jones.dk
Wed Feb 14 19:51:24 UTC 2018
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js pushed a commit to annotated tag debian/3.3.10-1
in repository uglifyjs.
commit 22aedef849e6e1ee8fd8c8ed0ccf27127eccd10a
Author: kzc <kzc at users.noreply.github.com>
Date: Sat May 20 10:09:21 2017 -0400
document minify() option `toplevel` (#1979)
---
README.md | 53 +++++++++++++++++++++++++++++++++--------------------
1 file changed, 33 insertions(+), 20 deletions(-)
diff --git a/README.md b/README.md
index f73bd27..2c6ee37 100644
--- a/README.md
+++ b/README.md
@@ -301,32 +301,45 @@ like this:
var UglifyJS = require("uglify-js");
```
-There is a single high level minification function, `minify(files, options)`, which will
+There is a single high level minification function, `minify(code, options)`, which will
performs all the steps in a configurable manner.
Example:
```javascript
-var result = UglifyJS.minify("var b = function() {};");
-console.log(result.code); // minified output
-console.log(result.error); // runtime error, if present
+var code = "function add(first, second) { return first + second; }";
+var result = UglifyJS.minify(code);
+console.log(result.error); // runtime error, or `undefined` if no error
+console.log(result.code); // minified output: function add(n,d){return n+d}
```
You can also compress multiple files:
```javascript
-var result = UglifyJS.minify({
- "file1.js": "var a = function() {};",
- "file2.js": "var b = function() {};"
-});
-console.log(result.code);
+var code = {
+ "file1.js": "function add(first, second) { return first + second; }",
+ "file2.js": "console.log(add(1 + 2, 3 + 4));"
+};
+var result = UglifyJS.minify(code);
+console.log(result.code); // function add(d,n){return d+n}console.log(add(3,7));
+```
+
+The `toplevel` option:
+```javascript
+var code = {
+ "file1.js": "function add(first, second) { return first + second; }",
+ "file2.js": "console.log(add(1 + 2, 3 + 4));"
+};
+var options = { toplevel: true };
+var result = UglifyJS.minify(code, options);
+console.log(result.code); // console.log(function(n,o){return n+o}(3,7));
```
To produce warnings:
```javascript
-var result = UglifyJS.minify("function f(){ var u; return 5; }", {
- warnings: true
-});
-console.log(result.code); // function f(){return 5}
+var code = "function f(){ var u; return 2 + 3; }";
+var options = { warnings: true };
+var result = UglifyJS.minify(code, options);
+console.log(result.error); // runtime error, `undefined` in this case
console.log(result.warnings); // [ 'Dropping unused variable u [0:1,18]' ]
-console.log(result.error); // runtime error, not defined in this case
+console.log(result.code); // function f(){return 5}
```
An error example:
@@ -338,7 +351,7 @@ console.log(JSON.stringify(result.error));
Note: unlike `uglify-js at 2.x`, the `3.x` API does not throw errors. To
achieve a similar effect one could do the following:
```javascript
-var result = UglifyJS.minify("if (0) else console.log(1);");
+var result = UglifyJS.minify(code, options);
if (result.error) throw result.error;
```
@@ -371,7 +384,7 @@ if (result.error) throw result.error;
- `ie8` (default `false`) - set to `true` to support IE8.
-## Minify option structure
+## Minify options structure
```javascript
{
@@ -526,8 +539,8 @@ If you're using the `X-SourceMap` header instead, you can just omit `sourceMap.u
- `cascade` -- small optimization for sequences, transform `x, x` into `x`
and `x = something(), x` into `x = something()`
-- `collapse_vars` -- Collapse single-use `var` and `const` definitions
- when possible.
+- `collapse_vars` -- Collapse single-use non-constant variables - side
+ effects permitting.
- `reduce_vars` -- Improve optimization on variables assigned with and
used as constant values.
@@ -749,8 +762,8 @@ Another way of doing that is to declare your globals as constants in a
separate file and include it into the build. For example you can have a
`build/defines.js` file with the following:
```javascript
-const DEBUG = false;
-const PRODUCTION = true;
+var DEBUG = false;
+var PRODUCTION = true;
// etc.
```
--
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