packages/babel-parser/src/util/location.js
// @flow
import { lineBreakG } from "./whitespace";
export type Pos = {
start: number,
};
// These are used when `options.locations` is on, for the
// `startLoc` and `endLoc` properties.
export class Position {
line: number;
column: number;
constructor(line: number, col: number) {
this.line = line;
this.column = col;
}
}
export class SourceLocation {
start: Position;
end: Position;
filename: string;
identifierName: ?string;
constructor(start: Position, end?: Position) {
this.start = start;
// $FlowIgnore (may start as null, but initialized later)
this.end = end;
}
}
// The `getLineInfo` function is mostly useful when the
// `locations` option is off (for performance reasons) and you
// want to find the line/column position for a given character
// offset. `input` should be the code string that the offset refers
// into.
export function getLineInfo(input: string, offset: number): Position {
let line = 1;
let lineStart = 0;
let match;
lineBreakG.lastIndex = 0;
while ((match = lineBreakG.exec(input)) && match.index < offset) {
line++;
lineStart = lineBreakG.lastIndex;
}
return new Position(line, offset - lineStart);
}