Location.ts

export type Range = [number, number]

type Position = {
    offset: number
    line: number
    column: number
}

export type Location = {
    start: Position
    end: Position
}

export function rangeToLocation(input: string, range: Range): Location {
    let startOffset = range[0]
    let start: Position = { offset: startOffset, line: 1, column: 1 }

    let p = 0
    while (p < startOffset) {
        if (input.charCodeAt(p) === 10) {
            start.line++
            start.column = 1
        } else {
            start.column++
        }
        p++
    }

    let endOffset = range[1]
    let end: Position = { ...start }
    while (p < endOffset) {
        if (input.charCodeAt(p) === 10) {
            end.line++
            end.column = 1
        } else {
            end.column++
        }
        p++
    }

    return { start, end }
}