I would like to measure time in browser javascript.
I use console.log(), console.debug() ...etc.
But console.timeEnd() behavior is similar to console.log(). It's wrote to console in case of "log" switch is on in browser's JS-Console. I need to write time to console only if debug messages has switched on in browser.
Is it possible somehow?
There's nothing built in that will do that for you, but it's very easy to implement it yourself: Maintain a Map of labels to start times, and use Date.now() or performance.now() to get the start and end times.
Very roughly:
const debugTimeMap = new Map();
const debugTime = label => {
if (debugTimeMap.has(label)) {
console.warn(`Timer '${label}' already exists`);
} else {
debugTimeMap.set(label, Date.now());
}
};
const debugTimeEnd = label => {
const start = debugTimeMap.get(label);
if (start === undefined) {
console.warn(`Invalid debugTime label "${label}"`);
} else {
debugTimeMap.delete(label);
console.debug(`${label}: ${Date.now() - start} ms`);
}
};
const debugTimeMap = new Map();
const debugTime = label => {
if (debugTimeMap.has(label)) {
console.warn(`Timer '${label}' already exists`);
} else {
debugTimeMap.set(label, Date.now());
}
};
const debugTimeEnd = label => {
const start = debugTimeMap.get(label);
if (start === undefined) {
console.warn(`Invalid debugTime label "${label}"`);
} else {
debugTimeMap.delete(label);
console.debug(`${label}: ${Date.now() - start} ms`);
}
};
debugTime("x");
setTimeout(() => {
debugTimeEnd("x");
}, Math.floor(Math.random() * 1000));(Look in the real console, and don't forget to turn on debug output in the console.)