ESPTerm web interface submodule, separated to make testing and development easier
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espterm-front-end/jssrc/utils.js

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/** Make a node */
function mk(e) {return document.createElement(e)}
/** Find one by query */
function qs(s) {return document.querySelector(s)}
/** Find all by query */
function qsa(s) {return document.querySelectorAll(s)}
/** Convert any to bool safely */
function bool(x) {
return (x === 1 || x === '1' || x === true || x === 'true');
}
/**
* Filter 'spacebar' and 'return' from keypress handler,
* and when they're pressed, fire the callback.
* use $(...).on('keypress', cr(handler))
*/
function cr(hdl) {
return function(e) {
if (e.which == 10 || e.which == 13 || e.which == 32) {
hdl();
}
};
}
/** Extend an objects with options */
function extend(defaults, options) {
var target = {};
Object.keys(defaults).forEach(function(k){
target[k] = defaults[k];
});
Object.keys(options).forEach(function(k){
target[k] = options[k];
});
return target;
}
/** Escape string for use as literal in RegExp */
function rgxe(str) {
return str.replace(/[\-\[\]\/\{\}\(\)\*\+\?\.\\\^\$\|]/g, "\\$&");
}
/** Format number to N decimal places, output as string */
function numfmt(x, places) {
var pow = Math.pow(10, places);
return Math.round(x*pow) / pow;
}
/** Get millisecond timestamp */
function msNow() {
return +(new Date);
}
/** Get ms elapsed since msNow() */
function msElapsed(start) {
return msNow() - start;
}
/** Shim for log base 10 */
Math.log10 = Math.log10 || function(x) {
return Math.log(x) / Math.LN10;
};
/**
* Perform a substitution in the given string.
*
* Arguments - array or list of replacements.
* Arguments numeric keys will replace {0}, {1} etc.
* Named keys also work, ie. {foo: "bar"} -> replaces {foo} with bar.
*
* Braces are added to keys if missing.
*
* @returns {String} result
*/
String.prototype.format = function () {
var out = this;
var repl = arguments;
if (arguments.length == 1 && (Array.isArray(arguments[0]) || typeof arguments[0] == 'object')) {
repl = arguments[0];
}
for (var ph in repl) {
if (repl.hasOwnProperty(ph)) {
var ph_orig = ph;
if (!ph.match(/^\{.*\}$/)) {
ph = '{' + ph + '}';
}
// replace all occurrences
var pattern = new RegExp(rgxe(ph), "g");
out = out.replace(pattern, repl[ph_orig]);
}
}
return out;
};
/** HTML escape */
function e(str) {
return $.htmlEscape(str);
}
/** Check for undefined */
function undef(x) {
return typeof x == 'undefined';
}
/** Safe json parse */
function jsp(str) {
try {
return JSON.parse(str);
} catch(e) {
console.error(e);
return null;
}
}
/** Create a character from ASCII code */
function Chr(n) {
return String.fromCharCode(n);
}
/** Decode number from 2B encoding */
function parse2B(s, i=0) {
return (s.charCodeAt(i++) - 1) + (s.charCodeAt(i) - 1) * 127;
}
/** Decode number from 3B encoding */
function parse3B(s, i=0) {
return (s.charCodeAt(i) - 1) + (s.charCodeAt(i+1) - 1) * 127 + (s.charCodeAt(i+2) - 1) * 127 * 127;
}
/** Encode using 2B encoding, returns string. */
function encode2B(n) {
var lsb, msb;
lsb = (n % 127);
n = ((n - lsb) / 127);
lsb += 1;
msb = (n + 1);
return Chr(lsb) + Chr(msb);
}
/** Encode using 3B encoding, returns string. */
function encode3B(n) {
var lsb, msb, xsb;
lsb = (n % 127);
n = (n - lsb) / 127;
lsb += 1;
msb = (n % 127);
n = (n - msb) / 127;
msb += 1;
xsb = (n + 1);
return Chr(lsb) + Chr(msb) + Chr(xsb);
}