Struct LazySourceMap 

pub struct LazySourceMap {
    pub file: Option<String>,
    pub source_root: Option<String>,
    pub sources: Vec<String>,
    pub sources_content: Vec<Option<String>>,
    pub names: Vec<String>,
    pub ignore_list: Vec<u32>,
    pub extensions: HashMap<String, Value>,
    pub debug_id: Option<String>,
    pub scopes: Option<ScopeInfo>,
    /* private fields */
}

A lazily-decoded source map that defers VLQ mappings decoding until needed.

For large source maps (100MB+), this avoids decoding all mappings upfront. JSON metadata (sources, names, etc.) is parsed eagerly, but VLQ mappings are decoded on a per-line basis on demand.

Examples

use srcmap_sourcemap::LazySourceMap;

let json = r#"{"version":3,"sources":["input.js"],"names":[],"mappings":"AAAA;AACA"}"#;
let sm = LazySourceMap::from_json(json).unwrap();

// Mappings are only decoded when accessed
let loc = sm.original_position_for(0, 0).unwrap();
assert_eq!(sm.source(loc.source), "input.js");

Fields

file: Option<String>

source_root: Option<String>

sources: Vec<String>

sources_content: Vec<Option<String>>

names: Vec<String>

ignore_list: Vec<u32>

extensions: HashMap<String, Value>

debug_id: Option<String>

scopes: Option<ScopeInfo>

Implementations

impl LazySourceMap

pub fn from_json(json: &str) -> Result<Self, ParseError>

Parse a source map from JSON, deferring VLQ mappings decoding.

Parses all JSON metadata eagerly but stores the raw mappings string. VLQ mappings are decoded per-line on demand.

pub fn decode_line(&self, line: u32) -> Result<Vec<Mapping>, DecodeError>

Decode a single line’s mappings on demand.

Returns the cached result if the line has already been decoded. The line index is 0-based.

pub fn original_position_for( &self, line: u32, column: u32, ) -> Option<OriginalLocation>

Look up the original source position for a generated position.

Both line and column are 0-based. Returns None if no mapping exists or the mapping has no source.

pub fn line_count(&self) -> usize

Number of generated lines in the source map.

pub fn source(&self, index: u32) -> &str

Resolve a source index to its filename.

Panics

Panics if index is out of bounds. Use get_source for a non-panicking alternative.

pub fn get_source(&self, index: u32) -> Option<&str>

Resolve a source index to its filename, returning None if out of bounds.

pub fn name(&self, index: u32) -> &str

Resolve a name index to its string.

Panics

Panics if index is out of bounds. Use get_name for a non-panicking alternative.

pub fn get_name(&self, index: u32) -> Option<&str>

Resolve a name index to its string, returning None if out of bounds.

pub fn source_index(&self, name: &str) -> Option<u32>

Find the source index for a filename.

pub fn mappings_for_line(&self, line: u32) -> Vec<Mapping>

Get all mappings for a line (decoding on demand).

pub fn into_sourcemap(self) -> Result<SourceMap, ParseError>

Fully decode all mappings into a regular SourceMap.

Useful when you need the full map after lazy exploration.

Trait Implementations

impl Debug for LazySourceMap

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.