Aspects for debugging

aop.js

// version 1.00

let indent = 0,
    LEVEL_0_COLOR = '#060dd3',
    LEVEL_X_COLOR = '#D33106',
    DLOG_DEBUG = true;

const START = '<',
      END = '>';


function dlog(message, level=0){
    if (DLOG_DEBUG) {
        const styles = [
            'border: 1px solid #3E0E02'
            , 'color: white'
            , 'display: block'
            , 'text-shadow: 0 1px 0 rgba(0, 0, 0, 0.3)'
            , 'box-shadow: 0 1px 0 rgba(255, 255, 255, 0.4) inset, 0 5px 3px -5px rgba(0, 0, 0, 0.5), 0 -13px 5px -10px rgba(255, 255, 255, 0.4) inset'
            , 'line-height: 20px'
            , 'text-align: center'
            , 'font-weight: bold'
        ];

        if (level==0) {
            styles.push(`background: linear-gradient(${LEVEL_0_COLOR}, #040647)`);
        } else {
            styles.push(`background: linear-gradient(${LEVEL_X_COLOR}, #571402)`);
        }
        
        const _styles = styles.join(';');
        console.log(`%c ${message}`, _styles);
    }
}


function dl(message, _indent=' ') {
    if (_indent == START) {
        indent += 1;
    }
    const prefix = ' '.repeat(indent*2);
    
    dlog(`${prefix} ${message}`);

    if (_indent == END) {
        indent -= 1;
    }
}      

function wrap_object(target) {
    // eg wrap_object(bl)
    dl('wrap_object');    
    /** Helping function used to get all methods of an object */
    const getMethods = (obj) => {
        let props = Object.getOwnPropertyNames(obj)
        if (props.length == 0) {
            props = Object.getOwnPropertyNames(Object.getPrototypeOf(obj));
        }
        return props.filter(item => typeof obj[item] === 'function');
    }
        
    
    /** Replace the original method with a custom function that will call our aspect when the advice dictates */
    function replaceMethod(target, methodName) {
        
        dl(`replaceMethod for object ${target}`);
        const originalCode = target[methodName]
        target[methodName] = (...args) => {
            dl(`${target.constructor.name}.${methodName} ( ${args} )`, START);
            
            const returnedValue = originalCode.apply(target, args)
            
            dl(`${target.constructor.name}.${methodName} return ${returnedValue} (type: ${typeof(returnedValue)})`, END);
            return returnedValue;
        }
    }
    const methods = getMethods(target)
    dl(`methods = ${methods}`);
    methods.forEach( m => {
        replaceMethod(target, m)
    })

}

function wrap(f) {
    dl(`wrap ${f}`)
    // eg test = wrap(test)
    const old_f = f;
    
    f = (...args) => {
        dl(`${old_f.name} ( ${args} )`, START);
        const result = old_f(args);
        dl(`${old_f.name} return ${result} (type: ${typeof result})`, END);
        return result;
    }
    return f
}

// version 1.00
// . initial release