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Description
Is your feature request related to a problem? Please describe.
Sometimes while logging, you want to use logger.debug, but you end up formatting a message even if the message won't be logged. Would be nice to make the formatting of the message content itself lazy.
Describe the solution you'd like
Use something like:
function template(strings, ...keys) {
return (...values) => {
const dict = values[values.length - 1] || {};
const result = [strings[0]];
keys.forEach((key, i) => {
const value = Number.isInteger(key) ? values[key] : dict[key];
result.push(value, strings[i + 1]);
});
return result.join("");
};
}
const t1Closure = template`${0}${1}${0}!`;
// const t1Closure = template(["","","","!"],0,1,0);
t1Closure("Y", "A"); // "YAY!"
const t2Closure = template`${0} ${"foo"}!`;
// const t2Closure = template([""," ","!"],0,"foo");
t2Closure("Hello", { foo: "World" }); // "Hello World!"
const t3Closure = template`I'm ${"name"}. I'm almost ${"age"} years old.`;
// const t3Closure = template(["I'm ", ". I'm almost ", " years old."], "name", "age");
t3Closure("foo", { name: "MDN", age: 30 }); // "I'm MDN. I'm almost 30 years old."
t3Closure({ name: "MDN", age: 30 }); // "I'm MDN. I'm almost 30 years old."Describe alternatives you've considered
Could also do logger.debug(() => ''), just a plain old function. But the templating idea seems pretty useful, at the end of the day it does in fact return a function too. So if you're going to template something, returning a function to be called might be faster if there are lots of logger.debug calls going around.
Additional context
- https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Template_literals#tagged_templates
Should benchmark if this really improves performance, but it also provides some usability... we might be more free to sprinkle logger.debug calls if they don't slow things down (except a function call).