mathjs/examples/function_transform.js at v1_develop · ThinkLib/mathjs · GitHub

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/**

* Function transforms

* When using functions via the expression parser, it is possible to preprocess

* function arguments and post process a functions return value by writing a

* *transform* for the function. A transform is a function wrapping around a

* function to be transformed or completely replaces a function.

var math = require('../index');

// create a function

function addIt(a, b) {

return a + b;

}

// attach a transform function to the function addIt

addIt.transform = function (a, b) {

console.log('input: a=' + a + ', b=' + b);

// we can manipulate the input arguments here before executing addIt

var res = addIt(a, b);

console.log('result: ' + res);

// we can manipulate the result here before returning

return res;

};

// import the function into math.js

math.import({

addIt: addIt

});

// use the function via the expression parser

console.log('Using expression parser:');

console.log('2+4=' + math.eval('addIt(2, 4)'));

// This will output:

// input: a=2, b=4

// result: 6

// 2+4=6

// when used via plain JavaScript, the transform is not invoked

console.log('');

console.log('Using plain JavaScript:');

console.log('2+4=' + math.addIt(2, 4));

// This will output:

// 6

mathjs/examples/function_transform.js at v1_develop · ThinkLib/mathjs · GitHub

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