web-console-logger 0.1.2

//! A logger for the wasm32-unknown-unknown target that prints all messages to
//! the web console
//!
//! ## Usage
//!
//! ```no_run
//! #[macro_use]
//! extern crate log;
//! extern crate web_console_logger;
//! extern crate wasm_bindgen;
//!
//! use wasm_bindgen::prelude::*;
//!
//! #[wasm_bindgen]
//! pub fn main() {
//!     web_console_logger::init().unwrap();
//!     // OR
//!     // web_console_logger::init_with_level(log::Level::Trace).unwrap();
//!
//!     trace!("This example message will be logged to the web browser's javascript console.");
//!
//!     web_console_logger::set_level(log::Level::Warn);
//!
//!     trace!("This will not be logged, because the log level is now `Warn`.");
//!     warn!("This will be logged, though.");
//! }
//! ```
//!
//! ## License
//!
//! Web Console Logger is licensed under either of
//!
//!  * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
//!    http://www.apache.org/licenses/LICENSE-2.0)
//!  * MIT license ([LICENSE-MIT](LICENSE-MIT) or
//!    http://opensource.org/licenses/MIT)
//!
//! at your option.

extern crate log;
extern crate wasm_bindgen;
extern crate web_sys;

use wasm_bindgen::prelude::*;

use log::{Level, Log, Metadata, Record, SetLoggerError};

struct WebConsoleLogger;

static LOGGER: WebConsoleLogger = WebConsoleLogger;

impl Log for WebConsoleLogger {
    fn enabled(&self, _metadata: &Metadata) -> bool {
        true
    }

    fn log(&self, record: &Record) {
        web_sys::console::log_1(&JsValue::from_str(
            format!(
                "{:<5} [{}] {}",
                record.level().to_string(),
                record.module_path().unwrap_or_default(),
                record.args()
            ).as_str(),
        ));
    }

    fn flush(&self) {}
}

/// Initializes logging with the provided maximum log level.
pub fn init_with_level(level: Level) -> Result<(), SetLoggerError> {
    log::set_logger(&LOGGER)?;
    log::set_max_level(level.to_level_filter());
    Ok(())
}

/// Initializes logging with a maximum log level of `Level::Trace`.
pub fn init() -> Result<(), SetLoggerError> {
    init_with_level(Level::Trace)
}

/// Dynamically set the log level.
pub fn set_level(level: Level) {
    log::set_max_level(level.to_level_filter());
}