2.8 KiB
@babel/code-frame
Generate errors that contain a code frame that point to source locations.
Install
npm install --save-dev @babel/code-frame
Usage
import { codeFrameColumns } from '@babel/code-frame';
const rawLines = `class Foo {
constructor()
}`;
const location = { start: { line: 2, column: 16 } };
const result = codeFrameColumns(rawLines, location, { /* options */ });
console.log(result);
1 | class Foo {
> 2 | constructor()
| ^
3 | }
If the column number is not known, you may omit it.
You can also pass an end
hash in location
.
import { codeFrameColumns } from '@babel/code-frame';
const rawLines = `class Foo {
constructor() {
console.log("hello");
}
}`;
const location = { start: { line: 2, column: 17 }, end: { line: 4, column: 3 } };
const result = codeFrameColumns(rawLines, location, { /* options */ });
console.log(result);
1 | class Foo {
> 2 | constructor() {
| ^
> 3 | console.log("hello");
| ^^^^^^^^^^^^^^^^^^^^^^^^^
> 4 | }
| ^^^
5 | };
Options
highlightCode
boolean
, defaults to false
.
Toggles syntax highlighting the code as JavaScript for terminals.
linesAbove
number
, defaults to 2
.
Adjust the number of lines to show above the error.
linesBelow
number
, defaults to 3
.
Adjust the number of lines to show below the error.
forceColor
boolean
, defaults to false
.
Enable this to forcibly syntax highlight the code as JavaScript (for non-terminals); overrides highlightCode
.
message
string
, otherwise nothing
Pass in a string to be displayed inline (if possible) next to the highlighted location in the code. If it can't be positioned inline, it will be placed above the code frame.
1 | class Foo {
> 2 | constructor()
| ^ Missing {
3 | };
Upgrading from prior versions
Prior to version 7, the only API exposed by this module was for a single line and optional column pointer. The old API will now log a deprecation warning.
The new API takes a location
object, similar to what is available in an AST.
This is an example of the deprecated (but still available) API:
import codeFrame from '@babel/code-frame';
const rawLines = `class Foo {
constructor()
}`;
const lineNumber = 2;
const colNumber = 16;
const result = codeFrame(rawLines, lineNumber, colNumber, { /* options */ });
console.log(result);
To get the same highlighting using the new API:
import { codeFrameColumns } from '@babel/code-frame';
const rawLines = `class Foo {
constructor() {
console.log("hello");
}
}`;
const location = { start: { line: 2, column: 16 } };
const result = codeFrameColumns(rawLines, location, { /* options */ });
console.log(result);