Struct js_source_scopes::SourceContext

pub struct SourceContext<T> { /* private fields */ }

A structure allowing fast line/column <-> byte offset remapping.

The primary use-case is to allow efficient conversion between SourcePositions (line/column) to byte offsets. The SourcePositions are 0-based. All offsets are treated as u32, and creating a SourceContext for a source that exceeds the range of a u32 will result in an Err.

Examples

use js_source_scopes::{SourceContext, SourcePosition};

let src = r#"const arrowFnExpr = (a) => a;
function namedFnDecl() {}"#;

let ctx = SourceContext::new(src).unwrap();

let offset = ctx.position_to_offset(SourcePosition::new(0, 6)).unwrap() as usize;
assert_eq!(&src[offset..offset+11], "arrowFnExpr");
let offset = ctx.position_to_offset(SourcePosition::new(1, 9)).unwrap() as usize;
assert_eq!(&src[offset..offset+11], "namedFnDecl");

Implementations

impl<T: AsRef<str>> SourceContext<T>

pub fn into_inner(self) -> T

Unwrap this Source Context into the inner source buffer.

pub fn new(src: T) -> Result<Self, SourceContextError>

Construct a new Source Context from the given src buffer.

pub fn offset_to_position(&self, offset: u32) -> Option<SourcePosition>

Converts a byte offset into the source to the corresponding line/column.

The column is given in UTF-16 code points.

pub fn position_to_offset(&self, position: SourcePosition) -> Option<u32>

Converts the given line/column to the corresponding byte offset inside the source.