@worker-tools/json-stream/script/json-path.js

Utilities for working with streaming JSON in Worker Runtimes such as Cloudflare Workers, Deno Deploy and Service Workers.

"use strict";
// deno-lint-ignore-file no-explicit-any no-prototype-builtins
Object.defineProperty(exports, "__esModule", { value: true });
exports.match = exports.normalize = exports.trace = void 0;
// Modernized version of Stefan Goessner's original JSON Path implementation.
// Copyright (c) 2007 Stefan Goessner (goessner.net)
// Licensed under the MIT license.
// TODO: refactor to avoid string splitting/joining
function* trace(expr, val, path) {
    if (expr) {
        const [loc, ...rest] = expr.split(";");
        const x = rest.join(";");
        if (val !== null && typeof val === 'object' && loc in val) {
            yield* trace(x, val[loc], path + ";" + loc);
        }
        else if (loc === "*") {
            for (const [m, _l, v, p] of walk(loc, val, path)) {
                yield* trace(m + ";" + x, v, p);
            }
        }
        else if (loc === "..") {
            yield* trace(x, val, path);
            for (const [m, _l, v, p] of walk(loc, val, path)) {
                if (typeof v[m] === "object")
                    yield* trace("..;" + x, v[m], p + ";" + m);
            }
        }
        else if (/,/.test(loc)) { // [name1,name2,...]
            for (let s = loc.split(/'?,'?/), i = 0, n = s.length; i < n; i++)
                yield* trace(s[i] + ";" + x, val, path);
        }
        else if (/^(-?[0-9]*):(-?[0-9]*):?([0-9]*)$/.test(loc)) { // [start:end:step] slice syntax
            yield* slice(loc, x, val, path);
        }
    }
    else
        yield [path, val];
}
exports.trace = trace;
function* slice(loc, expr, val, path) {
    if (val instanceof Array) {
        const len = val.length;
        let start = 0, end = len, step = 1;
        loc.replace(/^(-?[0-9]*):(-?[0-9]*):?(-?[0-9]*)$/g, (_$0, $1, $2, $3) => {
            start = parseInt($1 || start);
            end = parseInt($2 || end);
            step = parseInt($3 || step);
            return '';
        });
        start = (start < 0) ? Math.max(0, start + len) : Math.min(len, start);
        end = (end < 0) ? Math.max(0, end + len) : Math.min(len, end);
        for (let i = start; i < end; i += step)
            yield* trace(i + ";" + expr, val, path);
    }
}
function* walk(loc, val, path) {
    if (val instanceof Array) {
        for (let i = 0, n = val.length; i < n; i++)
            if (i in val)
                yield [i, loc, val, path];
    }
    else if (typeof val === "object") {
        for (const m in val)
            if (val.hasOwnProperty(m))
                yield [m, loc, val, path];
    }
}
function normalize(expr) {
    const subX = [];
    if (!expr.startsWith('$'))
        expr = '$' + expr;
    return expr
        .replace(/[\['](\??\(.*?\))[\]']/g, (_$0, $1) => { return "[#" + (subX.push($1) - 1) + "]"; })
        .replace(/'?\.'?|\['?/g, ";")
        .replace(/;;;|;;/g, ";..;")
        .replace(/;$|'?\]|'$/g, "")
        .replace(/#([0-9]+)/g, (_$0, $1) => { return subX[$1]; });
}
exports.normalize = normalize;
// FIXME: avoid repeated split/join/regex.test
function match(expr, path) {
    if (expr && path) {
        const [loc, ...restLoc] = expr.split(";");
        const [val, ...restVal] = path.split(";");
        const exprRest = restLoc.join(";");
        const pathRest = restVal.join(';');
        if (loc === val) {
            return match(exprRest, pathRest);
        }
        else if (loc === "*") {
            return match(exprRest, pathRest);
        }
        else if (loc === "..") {
            return match(exprRest, path) || match("..;" + exprRest, pathRest);
        }
        else if (/,/.test(loc)) { // [name1,name2,...]
            if (loc.split(/'?,'?/).some(v => v === val))
                return match(exprRest, pathRest);
            else
                return false;
        }
        else if (/^(-?[0-9]*):(-?[0-9]*):?([0-9]*)$/.test(loc)) { // [start:end:step] slice syntax
            let start = 0, end = Number.MAX_SAFE_INTEGER, step = 1;
            loc.replace(/^(-?[0-9]*):(-?[0-9]*):?(-?[0-9]*)$/g, (_$0, $1, $2, $3) => {
                start = parseInt($1 || start);
                end = parseInt($2 || end);
                step = parseInt($3 || step);
                return '';
            });
            const idx = Number(val);
            if (start < 0 || end < 0 || step < 0)
                throw TypeError('Negative numbers not supported. Can\'t know length ahead of time when stream parsing');
            if (idx >= start && idx < end && start + idx % step === 0)
                return match(exprRest, pathRest);
            else
                return false;
        }
    }
    else if (!expr && !path)
        return true;
    return false;
}
exports.match = match;
//# sourceMappingURL=json-path.js.map