Console

The Console module provides standard console output functionality for debugging and logging, similar to browser console APIs.

Console Object

console.log(...args)

Outputs messages to both the serial console and display (depending on configuration). The primary logging function for debugging.

Parameters:

Parameter	Type	Description
...args	any	Any number of values to output

Returns: None

Example:

// Basic logging
console.log("Hello, World!");

// Multiple arguments
console.log("Counter:", 42, "Status:", true);

// Objects and arrays
var user = { name: "Alice", age: 30 };
var numbers = [1, 2, 3, 4, 5];
console.log("User:", user);
console.log("Numbers:", numbers);

// Variables and expressions
var x = 10, y = 20;
console.log("Sum:", x + y);
console.log("Result:", x * y > 100 ? "Large" : "Small");

Global Print Functions

print(...args)

Outputs values without a newline. Useful for building output line by line.

Parameters:

Parameter	Type	Description
...args	any	Any number of values to output

Returns: None

Example:

// Single line output
print("Loading");
print(".");
print(".");
print(".");
print(" Complete!");

// Building formatted output
var progress = 75;
print("Progress: [");
for (var i = 0; i < 20; i++) {
    print(i < progress / 5 ? "█" : "░");
}
print("] " + progress + "%");

println(...args)

Outputs values followed by a newline. Equivalent to console.log().

Parameters:

Parameter	Type	Description
...args	any	Any number of values to output

Returns: None

Example:

// Line-by-line output
println("System Status:");
println("CPU: OK");
println("Memory: OK");
println("Storage: OK");

// Formatted logging
var timestamp = Date.now();
println("[" + timestamp + "] Application started");

Console Applications

System Monitor

var display = require("display");
var keyboard = require("keyboard");

function systemMonitor() {
    var startTime = Date.now();
    var loopCount = 0;

    console.log("=== System Monitor Started ===");
    console.log("Start Time:", Date.now());

    while (true) {
        if (keyboard.getEscPress()) break;

        loopCount++;
        var uptime = Date.now() - startTime;

        // Display status line
        display.println("Uptime: " + formatUptime(uptime));
        display.println(" | Loops: " + loopCount);
        display.println(" | Avg: " + (uptime / loopCount).toFixed(1) + "ms");
        display.println(" | Press Back to exit");

        delay(100);
    }

    console.log("=== System Monitor Stopped ===");
    console.log("Total uptime:", formatUptime(Date.now() - startTime));
    console.log("Total loops:", loopCount);
}

function formatUptime(ms) {
    var seconds = Math.floor(ms / 1000);
    var minutes = Math.floor(seconds / 60);
    var hours = Math.floor(minutes / 60);

    if (hours > 0) {
        return hours + "h " + (minutes % 60) + "m " + (seconds % 60) + "s";
    } else if (minutes > 0) {
        return minutes + "m " + (seconds % 60) + "s";
    } else {
        return seconds + "s";
    }
}

// Start monitoring
systemMonitor();

Data Table Formatter

function TableFormatter(headers) {
    this.headers = headers;
    this.rows = [];
    this.columnWidths = [];
    for (var i = 0; i < headers.length; i++) {
        this.columnWidths.push(headers[i].length);
    }
}

TableFormatter.prototype.addRow = function(row) {
    if (row.length !== this.headers.length) {
        throw new Error("Row length doesn't match headers");
    }

    var stringRow = [];
    for (var i = 0; i < row.length; i++) {
        stringRow.push(String(row[i]));
    }
    this.rows.push(stringRow);

    // Update column widths
    for (var i = 0; i < row.length; i++) {
        this.columnWidths[i] = Math.max(
            this.columnWidths[i],
            String(row[i]).length
        );
    }
};

TableFormatter.prototype.print = function() {
    var separator = "+";
    for (var i = 0; i < this.columnWidths.length; i++) {
        var dashes = "";
        for (var j = 0; j < this.columnWidths[i] + 2; j++) {
            dashes += "-";
        }
        separator += dashes + "+";
    }

    // Top border
    console.log(separator);

    // Headers
    this.printRow(this.headers);
    console.log(separator);

    // Data rows
    for (var i = 0; i < this.rows.length; i++) {
        this.printRow(this.rows[i]);
    }

    // Bottom border
    console.log(separator);
};

TableFormatter.prototype.printRow = function(row) {
    var line = "|";
    for (var i = 0; i < row.length; i++) {
        var cell = String(row[i]);
        var padding = "";
        for (var j = 0; j < this.columnWidths[i] - cell.length; j++) {
            padding += " ";
        }
        line += " " + cell + padding + " |";
    }
    console.log(line);
};

// Usage example
function networkStatus() {
    const table = new TableFormatter(["Interface", "Status", "IP", "Signal"]);

    table.addRow(["WiFi", "Connected", "192.168.1.100", "-45 dBm"]);
    table.addRow(["Bluetooth", "Disconnected", "-", "N/A"]);
    table.addRow(["USB", "Connected", "10.0.0.1", "N/A"]);

    console.log("Network Interface Status:");
    table.print();
}

networkStatus();

Log Analysis

function logAnalyzer(logData) {
    var lines = logData.split("\n");

    var analysis = {
        totalLines: lines.length,
        errorCount: 0,
        warningCount: 0,
        infoCount: 0,
        debugCount: 0,
        patterns: {}
    };

    console.log("Analyzing log data...");

    var i, j, line, matches, match;

    for (i = 0; i < lines.length; i++) {
        line = lines[i];

        /* Manual trim check (no String.trim) */
        if (!line || line.replace(/\s/g, "") === "") {
            continue;
        }

        /* Log level counting (no includes) */
        if (line.indexOf("[ERROR]") !== -1) {
            analysis.errorCount++;
        } else if (line.indexOf("[WARN]") !== -1) {
            analysis.warningCount++;
        } else if (line.indexOf("[INFO]") !== -1) {
            analysis.infoCount++;
        } else if (line.indexOf("[DEBUG]") !== -1) {
            analysis.debugCount++;
        }

        /* Pattern matching */
        matches = line.match(/\b\w+Exception\b|\b\w+Error\b/g);
        if (matches) {
            for (j = 0; j < matches.length; j++) {
                match = matches[j];
                if (analysis.patterns[match]) {
                    analysis.patterns[match]++;
                } else {
                    analysis.patterns[match] = 1;
                }
            }
        }
    }

    /* Display results */
    console.log("\n=== Log Analysis Results ===");
    console.log("Total lines:", analysis.totalLines);
    console.log("Errors:", analysis.errorCount);
    console.log("Warnings:", analysis.warningCount);
    console.log("Info:", analysis.infoCount);
    console.log("Debug:", analysis.debugCount);

    /* Check if patterns exist (no Object.keys) */
    var hasPatterns = false;
    for (match in analysis.patterns) {
        hasPatterns = true;
        break;
    }

    if (hasPatterns) {
        console.log("\nError patterns:");
        for (match in analysis.patterns) {
            console.log("  " + match + ":", analysis.patterns[match]);
        }
    }

    /* Health score */
    var total = analysis.errorCount + analysis.warningCount + analysis.infoCount;
    var healthScore = 100;

    if (total > 0) {
        healthScore = Math.round((1 - (analysis.errorCount / total)) * 100);
    }

    console.log("\nSystem health score:", healthScore + "%");

    return analysis;
}

var sampleLog =
"[2024-01-30T10:00:00Z] [INFO] System started\n" +
"[2024-01-30T10:00:01Z] [DEBUG] Loading modules\n" +
"[2024-01-30T10:00:02Z] [WARN] Low battery detected\n" +
"[2024-01-30T10:00:03Z] [ERROR] ConnectionException: Failed to connect\n" +
"[2024-01-30T10:00:04Z] [INFO] Retrying connection\n" +
"[2024-01-30T10:00:05Z] [ERROR] TimeoutError: Request timed out";

var analysis = logAnalyzer(sampleLog);

Output Formatting

Formatting Utilities

/* String formatting helpers */

function pad(str, length, char) {
    if (char === undefined) {
        char = " ";
    }

    str = String(str);

    while (str.length < length) {
        str = char + str;
    }

    return str;
}

function formatBytes(bytes) {
    var units = ["B", "KB", "MB", "GB"];
    var size = bytes;
    var unitIndex = 0;

    while (size >= 1024 && unitIndex < units.length - 1) {
        size = size / 1024;
        unitIndex++;
    }

    return size.toFixed(1) + " " + units[unitIndex];
}

function formatDuration(ms) {
    if (ms < 1000) {
        return ms + "ms";
    }

    if (ms < 60000) {
        return (ms / 1000).toFixed(1) + "s";
    }

    if (ms < 3600000) {
        return Math.floor(ms / 60000) + "m " +
               Math.floor((ms % 60000) / 1000) + "s";
    }

    var hours = Math.floor(ms / 3600000);
    var minutes = Math.floor((ms % 3600000) / 60000);

    return hours + "h " + minutes + "m";
}

/* Usage in console output */

function systemReport() {
    var now = Date.now();

    console.log("=== System Report ===");
    console.log("Uptime:", formatDuration(now));
    console.log("Memory:", formatBytes(512000), "used of", formatBytes(1048576));
    console.log("CPU:", pad("85%", 6), "load");
    console.log("Temperature:", pad("42°C", 6));
}

systemReport();