ow/dist/utils/infer-label.js

Function argument validation for humans

import fs from 'node:fs';
import { isNode } from 'environment';
import isIdentifier from 'is-identifier';
// Regex to extract the label out of the `ow` function call
const labelRegex = /^.*?\((?<label>.*?)[,)]/;
/**
Infer the label of the caller.

@hidden

@param callsites - List of stack frames.
*/
export const inferLabel = (callsites) => {
    if (!isNode) {
        // Exit if we are not running in a Node.js environment
        return;
    }
    // Grab the stackframe with the `ow` function call
    const functionCallStackFrame = callsites[1];
    if (!functionCallStackFrame) {
        return;
    }
    const fileName = functionCallStackFrame.getFileName();
    const lineNumber = functionCallStackFrame.getLineNumber();
    const columnNumber = functionCallStackFrame.getColumnNumber();
    if (fileName === null || lineNumber === null || columnNumber === null) {
        return;
    }
    let content = [];
    try {
        content = fs.readFileSync(fileName, 'utf8').split('\n');
    }
    catch {
        return;
    }
    let line = content[lineNumber - 1];
    if (!line) {
        // Exit if the line number couldn't be found
        return;
    }
    line = line.slice(columnNumber - 1);
    const match = labelRegex.exec(line);
    const token = match?.groups?.['label'];
    if (!token) {
        // Exit if we didn't find a label
        return;
    }
    // @ts-expect-error - Doesn't seem like something I can work around.
    if (isIdentifier(token) || isIdentifier(token.split('.').pop() ?? '')) { // eslint-disable-line @typescript-eslint/no-unsafe-call
        return token;
    }
    return;
};