mathjs
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Math.js is an extensive math library for JavaScript and Node.js. It features a flexible expression parser and offers an integrated solution to work with numbers, big numbers, complex numbers, units, and matrices.
131 lines (110 loc) • 3.31 kB
HTML
<html>
<head>
<title>math.js | angle configuration</title>
<style>
body, input, select {
font: 11pt sans-serif;
}
input, select, th, #result {
padding: 5px 10px;
}
th {
text-align: left;
}
</style>
<script src="../../dist/math.js"></script>
</head>
<body>
<p>
This code example extends the trigonometric functions of math.js with configurable angles: degrees, radians, or gradians.
</p>
<table>
<tr>
<th>Angles</th>
<td>
<select id="angles">
<option value="deg">deg</option>
<option value="grad">grad</option>
<option value="rad">rad</option>
</select>
</td>
</tr>
<tr>
<th>Expression</th>
<td>
<input id="expression" type="text" value="sin(45)" />
<input id="evaluate" type="button" value="Evaluate">
</td>
</tr>
<tr>
<th>Result</th>
<td id="result"></td>
</tr>
</table>
<script>
var replacements = {};
// our extended configuration options
var config = {
angles: 'deg' // 'rad', 'deg', 'grad'
};
// create trigonometric functions replacing the input depending on angle config
['sin', 'cos', 'tan', 'sec', 'cot', 'csc'].forEach(function(name) {
var fn = math[name]; // the original function
replacements[name] = function replacement(x) {
if (x instanceof math.type.BigNumber) {
x = x.toNumber(); // convert to number
}
if (typeof x === 'boolean') {
x = +x; // convert to number
}
if (typeof x === 'number') {
// convert from configured type of angles to radians
switch(config.angles) {
case 'deg': return fn(x / 360 * 2 * Math.PI);
case 'grad': return fn(x / 400 * 2 * Math.PI);
default: return fn(x);
}
}
if (math.collection.isCollection(x)) {
return math.collection.deepMap(x, replacement);
}
return fn(x);
};
});
// create trigonometric functions replacing the output depending on angle config
['asin', 'acos', 'atan', 'atan2'].forEach(function(name) {
var fn = math[name]; // the original function
replacements[name] = function replacement(x) {
var result = fn(x);
if (typeof result === 'number') {
// convert to radians to configured type of angles
switch(config.angles) {
case 'deg': return result / 2 / Math.PI * 360;
case 'grad': return result / 2 / Math.PI * 400;
default: return result;
}
}
if (math.collection.isCollection(x)) {
return math.collection.deepMap(x, replacement);
}
return result;
};
});
// import all replacements into math.js, override existing trigonometric functions
math.import(replacements, {override: true});
// pointers to the input elements
var expression = document.getElementById('expression');
var evaluate = document.getElementById('evaluate');
var result = document.getElementById('result');
var angles = document.getElementById('angles');
// attach event handlers for select box and button
angles.onchange = function () {
config.angles = this.value;
};
evaluate.onclick = function () {
result.innerHTML = math.eval(expression.value);
};
</script>
</body>
</html>