Source code
Revision control
Copy as Markdown
Other Tools
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
import { parseJsonLossless } from "resource://devtools/client/shared/components/reps/reps/rep-utils.mjs";
// Brands JsonlLineError instances so they can be recognized across module
// instances, where `instanceof` would fail.
const JSONL_LINE_ERROR = Symbol.for("devtools.jsonl.lineError");
/**
* Represents one line of a JSON Lines document that failed to parse
* as JSON. `raw` and `message` are non-enumerable so this behaves as
* a leaf node in the JSON tree view (no expand toggle, no children).
*/
export class JsonlLineError {
/**
* @param {string} raw
* The line's original text.
* @param {string} message
* The parse error message reported for that line.
*/
constructor(raw, message) {
Object.defineProperties(this, {
raw: { value: raw, enumerable: false },
message: { value: message, enumerable: false },
[JSONL_LINE_ERROR]: { value: true, enumerable: false },
});
}
static isInstance(value) {
return !!value?.[JSONL_LINE_ERROR];
}
toJSON() {
return { error: this.message, raw: this.raw };
}
}
/**
* Parses a JSON Lines document (one JSON value per line) into an
* array of records, in document order. Blank lines are skipped, so
* the array is contiguous and displayed like any other JSON array.
* A line that fails to parse becomes a JsonlLineError instead of
* blocking the rest of the document.
*
* @param {string} jsonlinesText
* The whole JSON Lines document, as text.
* @returns {Array<object|JsonlLineError>}
* One entry per non-blank line, in document order.
*/
export function parseJsonl(jsonlinesText) {
const entries = [];
const lines = jsonlinesText.split("\n");
for (let i = 0; i < lines.length; i++) {
const line = lines[i];
if (!line.trim()) {
continue;
}
try {
entries.push(parseJsonLossless(line));
} catch (err) {
entries.push(
new JsonlLineError(line, documentLineErrorMessage(err, line, i))
);
}
}
return entries;
}
/**
* Returns the parse error message for a line which failed to parse, pointing at
* the line's position in the document. The line is reparsed preceded by the
* blank lines it comes after, since a parser fed a single line can only ever
* report line 1.
*
* @param {Error} err
* The error thrown when parsing the line on its own.
* @param {string} line
* The line's text.
* @param {number} lineIndex
* The 0-based position of the line in the document.
* @returns {string}
* The parse error message.
*/
function documentLineErrorMessage(err, line, lineIndex) {
if (!lineIndex) {
return err.message;
}
try {
parseJsonLossless("\n".repeat(lineIndex) + line);
} catch (paddedErr) {
return paddedErr.message;
}
return err.message;
}