dockerized_openAger/nodered/rootfs/data/node_modules/mathjs/examples/chaining.js
2020-10-17 18:42:50 +02:00

59 lines
1.5 KiB
JavaScript

// chaining
// load math.js (using node.js)
var math = require('../index');
// create a chained operation using the function `chain(value)`
// end a chain using done(). Let's calculate (3 + 4) * 2
var a = math.chain(3)
.add(4)
.multiply(2)
.done();
print(a); // 14
// Another example, calculate square(sin(pi / 4))
var b = math.chain(math.pi)
.divide(4)
.sin()
.square()
.done();
print(b); // 0.5
// A chain has a few special methods: done, toString, valueOf, get, and set.
// these are demonstrated in the following examples
// toString will return a string representation of the chain's value
var chain = math.chain(2).divide(3);
var str = chain.toString();
print(str); // "0.6666666666666666"
// a chain has a function .valueOf(), which returns the value hold by the chain.
// This allows using it in regular operations. The function valueOf() acts the
// same as function done().
print(chain.valueOf()); // 0.66666666666667
print(chain + 2); // 2.6666666666667
// the function subset can be used to get or replace sub matrices
var array = [[1, 2], [3, 4]];
var v = math.chain(array)
.subset(math.index(1, 0))
.done();
print(v); // 3
var m = math.chain(array)
.subset(math.index(0, 0), 8)
.multiply(3)
.done();
print(m); // [[24, 6], [9, 12]]
/**
* Helper function to output a value in the console. Value will be formatted.
* @param {*} value
*/
function print (value) {
var precision = 14;
console.log(math.format(value, precision));
}