user142686

Most recent activity

• Number.toFixed() not rounding per specification

  in JavaScript • 2 years

  

  It seems like Math.round() is a better solution, but it is not! In some cases it will NOT round correctly. Also, toFixed() will NOT round correctly in some cases.

  To correct the rounding problem with the previous Math.round() and toFixed(), you can define a custom JavaScript round function that performs a "nearly equal" test to determine whether a fractional value is sufficiently close to a midpoint value to be subject to midpoint rounding. The following function return the value of the given number rounded to the nearest integer accurately.

  Number.prototype.roundTo = function(decimal) {
    return +(Math.round(this + "e+" + decimal)  + "e-" + decimal);
  }
  
  var num = 9.7654;
  console.log( num.roundTo(2)); //output 9.77
  

• How to use spi to write and read some specfic register address

  in Pico / Wifi / Original Espruino • 2 years

  

  setTimeout() and setInterval() functions allow you to execute a piece of JavaScript code/function at a certain point in the future. setInterval repeats the call, setTimeout only runs it once.

  JavaScript setTimeout(expression, timeout); runs the code/function once after the timeout. It is a time based code execution method that will execute script only one time when the interval is reached, and not repeat again unless you gear it to loop the script by nesting the setTimeout object inside of the function it calls to run. If geared to loop, it will keep firing at the interval unless you call clearTimeout(). If you want something to happen one time after some seconds Then use setTimeout... because it only executes one time when the interval is reached.

  setTimeout(function() {
    console.log('Wait 3 seconds and I appear just once');
  }, 3000);
  

  setInterval(expression, timeout); runs the code/function repeatedly, with the length of the timeout between each repeat. It is a time interval based code execution method that has the native ability to repeatedly run specified script when the interval is reached. It should not be nested into its callback function by the script author to make it loop, since it loops by default. It will keep firing at the interval unless you call clearInterval(). If you want to loop code for animations or clocks Then use setInterval.

  setInterval(function() {
    console.log('Every 3 seconds I appear on your console');
  }, 3000)