JavaScript - convert string to boolean

var text = 'true';

​

console.log(text === 'true');  // true

function parseBoolean(text) {

    var value = JSON.parse(text);

    if(typeof value !== 'boolean') {

        throw new Error('Incorrect type!');

    }

    return value;

}

​

​

// Usage example:

​

var text = 'true';

var value = parseBoolean(text);

​

console.log(value);  // true

var truthExpression = /^(TRUE|True|true|YES|Yes|yes|ON|On|on|1|T|t|Y|y)$/g;

var falsyExpression = /^(FALSE|False|false|NO|No|no|OFF|Off|off|0|F|f|N|n)$/g;

​

function parseBoolean(text) {

    if (truthExpression.test(text)) {

        return true;

    }

    if (falsyExpression.test(text)) {

        return false;

    }

    throw new Error('Incorrect value!');

}

​

​

// Usage example:

​

var text = 'true';

var value = parseBoolean(text);

​

console.log(value);  // true

function parseBoolean(value) {

    switch(value) {

        case 1:

        case true:

        case "1":

        case "true":

        case "True":

        case "TRUE":

        case "on":

        case "On":

        case "ON":

        case "yes":

        case "Yes":

        case "YES":

        case "t":

        case "T":

        case "y":

        case "Y":

            return true;

        case 0:

        case false:

        case "0":

        case "false":

        case "False":

        case "FALSE":

        case "off":

        case "Off":

        case "OFF":

        case "no":

        case "No":

        case "NO":

        case "f":

        case "F":

        case "n":

        case "N":

            return false;

        default:

            throw new Error('Incorrect value!');

    }

}

​

​

// Usage example:

​

var text = 'true';

var value = parseBoolean(text);

​

console.log(value);  // true