pxt-ev3/libs/core/console.ts

/// <reference no-default-lib="true"/>

/**
 * Reading and writing data to the console output.
 */
//% weight=12 color=#00451A icon="\uf112"
//% advanced=true
namespace console {
    type Listener = (text: string) => void;

    const listeners: Listener[] = [
        (text: string) => serial.writeLine(text)
    ];

    /**
     * Write a line of text to the console output.
     * @param value to send
     */
    //% weight=90
    //% help=console/log blockGap=8
    //% blockId=console_log block="console|log %text"
    export function log(text: string): void {
        for (let i = 0; i < listeners.length; ++i)
            listeners[i](text);
    }

    /**
     * Write a name:value pair as a line of text to the console output.
     * @param name name of the value stream, eg: "x"
     * @param value to write
     */
    //% weight=88 blockGap=8
    //% help=console/log-value
    //% blockId=console_log_value block="console|log value %name|= %value"
    export function logValue(name: string, value: number): void {
        log(`${name}: ${value}`)
    }

    /**
     * Adds a listener for the log messages
     * @param listener 
     */
    //%
    export function addListener(listener: (text: string) => void) {
        if (!listener) return;
        listeners.push(listener);
    }
}