mirror of
https://github.com/RGBCube/serenity
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66 lines
1.7 KiB
Markdown
66 lines
1.7 KiB
Markdown
## Name
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js - evaluate JavaScript
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## Synopsis
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```**sh
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$ js [options...] [script.js]
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```
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## Description
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`js` evaluates JavaScript programs using the LibJS engine. If you pass it a path
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to a script file, it will execute that script. Otherwise, it enters the
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Read-Eval-Print-Loop (REPL) mode, where it interactively reads pieces (usually,
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single lines) of code from standard input, evaluates them in one shared
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interpreter context, and prints back their results. This mode is useful for
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quickly experimenting with LibJS.
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Run `help()` in REPL mode to see its available built-in functions.
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## Options
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* `-A`, `--dump-ast`: Dump the Abstract Syntax Tree after parsing the program.
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* `-d`, `--dump-bytecode`: Dump the bytecode
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* `-b`, `--run-bytecode`: Run the bytecode
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* `-p`, `--optimize-bytecode`: Optimize the bytecode
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* `-m`, `--as-module`: Treat as module
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* `-l`, `--print-last-result`: Print the result of the last statement executed.
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* `-g`, `--gc-on-every-allocation`: Run garbage collection on every allocation.
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* `-i`, `--disable-ansi-colors`: Disable ANSI colors
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* `-h`, `--disable-source-location-hints`: Disable source location hints
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* `-s`, `--no-syntax-highlight`: Disable live syntax highlighting in the REPL
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* `-c`, `--evaluate`: Evaluate the argument as a script
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## Examples
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Here's how you execute a script from a file:
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```sh
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$ js ~/Source/js/type-play.js
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```
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Here's how you execute a script as a command line argument:
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```sh
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$ js -c "console.log(42)"
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42
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```
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And here's an example of an interactive REPL session:
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```js
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$ js
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> function log_sum(a, b) {
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> console.log(a + b)
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> }
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undefined
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> log_sum(35, 42)
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77
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undefined
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```
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## See also
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* [`test-js`(1)](help://man/1/test-js)
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