Method sourceAround

src/common/debug.ts:84–141

line: 1..., column: 1...

(line: number, column: number, message?: string)

  /** line: 1..., column: 1... */
  sourceAround(line: number, column: number, message?: string): string {
    const linesAbove = 2;
    const linesBelow = 3;
    const start = Math.max(line - 1 - (linesAbove + 1), 0);
    const end = Math.min(this.lines.length, line + linesBelow) - 1;

    const hasColumn = typeof column === 'number';
    const numberMaxWidth = String(end).length;
    const result: string[] = [];
    // index = 0..., start = 0... end = 0...
    for (let index = start; index <= end; index++) {
      const paddedNumber = ` ${index + 1}`.slice(-numberMaxWidth);
      const gutter = ` ${paddedNumber} \u2506 `;
      let markerLine = '';
      if (index === line - 1) {
        if (hasColumn) {
          const markerSpacing = this.lines[index]
            .slice(0, Math.max(column - 1, 0))
            .replace(/[^\t]/g, ' ');
          markerLine =
            '\n ' +
            this.chalkGutter(gutter.replace(/\d/g, ' ')) +
            markerSpacing +
            this.chalkMarker('^');

          if (message) {
            markerLine += ' ' + this.chalkMessage(message);
          }
        } else if (message) {
          markerLine =
            '\n' + this.chalkGutter(gutter.replace(/\d/g, ' ')) + message;
        }
        result.push(
          [
            this.chalkMarker('>'),
            this.chalkGutter(gutter),
            this.lines[index],
            markerLine,
          ].join('')
        );
      } else {
        result.push(` ${this.chalkGutter(gutter)}${this.lines[index]}`);
      }
    }
    return terminal.renderBlock({
      tag: 'block',
      spans: result.map((line) => ({ content: line + '\n' })),
    });
    /**
  1111 |     expect(
    12 |       rawExpression('\\sqrt{(1+x_0)}=\\frac{\\pi^2}{2}')
  > 13 |     ).toMatchInlineSnapshot(
       |       ^
    14 |       `'["Latex","\\\\sqrt","<{>","(",1,"+","x","_",0,")","<}>","=","\\\\frac","<{>","\\\\pi","^",2,"<}>","<{>",2,"<}>"]'`
    15 |     );
    16 |   });
    */
  }