@beenotung/tslib/buffered-cli.js

utils library in Typescript

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.BufferedCli = void 0;
/**
 * - Print the buffer to cli output stream.
 * - Reset the cursor to the beginning without using `console.clear()` to avoid flickering.
 * - Not accurate, when tab (`\t`) is used without `writeln()` nor newline (`\n`).
 */
class BufferedCli {
    out;
    buffer = '';
    lastBuffer = '';
    constructor(out = process.stdout) {
        this.out = out;
    }
    write(message) {
        this.buffer += message;
    }
    writeln(message) {
        this.write(message + '\n');
    }
    render(buffer, lastLines) {
        const columns = this.out.columns;
        let x = 0;
        let y = 0;
        let output = '';
        const lines = [];
        for (const char of buffer) {
            if (char == '\n') {
                // early jump to next line, may need to fill extra spaces
                const lastX = lastLines[y];
                if (lastX > x) {
                    output += ' '.repeat(lastX - x);
                }
                output += '\n';
                lines.push(x);
                x = 0;
                y++;
                continue;
            }
            // add new char to the current line
            output += char;
            x++;
            if (x == columns) {
                // used full line, move to next line
                lines.push(x);
                x = 0;
                y++;
            }
        }
        lines.push(x);
        return { output, x, y, lines };
    }
    flush() {
        const { out, buffer, lastBuffer } = this;
        const last = this.render(lastBuffer, []);
        const current = this.render(buffer, last.lines);
        if (last.y == 0) {
            out.moveCursor(-last.x, 0);
        }
        else {
            out.moveCursor(0, -last.y);
            out.cursorTo(0);
        }
        let output = current.output;
        let extra = 0;
        if (!output.endsWith('\n')) {
            const currentTail = getTailLength(output);
            const lastTail = getTailLength(last.output);
            extra = lastTail - currentTail;
            if (extra > 0) {
                output += ' '.repeat(extra);
            }
        }
        out.write(output);
        if (extra > 0) {
            out.moveCursor(-extra, 0);
        }
        this.lastBuffer = buffer;
        this.buffer = '';
    }
    end() {
        const { out, lastBuffer } = this;
        if (!lastBuffer.endsWith('\n')) {
            out.write('\n');
        }
    }
}
exports.BufferedCli = BufferedCli;
function getTailLength(text) {
    const index = text.lastIndexOf('\n');
    if (index === -1) {
        return text.length;
    }
    else {
        return text.length - index - 1;
    }
}