gulp-math

Evaluate math expressions with gulp

gulp-math makes use of the Math.js library for Javascript and Node.js. Their documentation can be used to form the math expressions used by gulp-math.

Usage

First, install gulp-math as a development dependency:

npm install gulp-math

Then, add it to your gulpfile.js:

var math = require('gulp-math');

gulp.task('generate', function() {
    return gulp.src('pre.html')
        .pipe(math({columns: 12, column_padding: 20, max_content_width: 660}).on('error', function(err) {
            console.log(err.toString());
            this.emit('end');
        }))
        .pipe(gulp.dest(''));
});

Now, use gulpmath(); in your code:

gulpmath(10 * 2 - 5 / 3);

Options

gulp-math accepts a list of variables to be used in the calculations.

math(vars[, options])

vars

Type: Array Object

An associative array of variables to be used in the math expressions. The keys will be used as variable names.

.pipe(math({columns: 12, column_padding: 20, max_content_width: 660}))

options

Type: Array Object

An associative array of option used by the plugin. All Math.js configuration options are available. Documentation for Math.js options are taken directly from their site. Please note, gulp-math uses the eval function for evaluating expressions.

options.epsilon

Type: Number Default: 1e-14

The minimum relative difference used to test equality between two compared values. This value is used by all relational functions.

options.eval_precision

Type: Integer Default: 3 Available values: 0-15

The number of decimal places used when evaluating expressions. This option will only be used if options.number is set to number.

options.matrix

Type: String Default: matrix Available values: matrix or array

The default type of matrix output for functions. Available values are: matrix (default) or array. Where possible, the type of matrix output from functions is determined from the function input: An array as input will return an Array, a Matrix as input will return a Matrix. In case of no matrix as input, the type of output is determined by the option matrix. In case of mixed matrix inputs, a matrix will be returned always.

options.number

Type: String Default: number Available values: number or bignumber

The default type of numbers. This setting is used by functions like eval which cannot determine the correct type of output from the functions input. For most functions though, the type of output is determined from the the input: a number as input will return a number as output, a BigNumber as input returns a BigNumber as output. Available values are: number (default) or bignumber. BigNumbers have higher precision than the default numbers of JavaScript.

options.precision

Type: Integer Default: 64

The maximum number of significant digits for bigNumbers. This setting only applies to BigNumbers, not to numbers. Default value is 64.

Example

An HTML file with the following markup:

<div>
    gulpmath(abc = 5);
    <p>There are gulpmath(10 * 2 - abc); meese in the lodge.</p>
</div>

Will output the following:

<div>
    <p>There are 15 meese in the lodge.</p>
</div>

You can escape semi-colons in your expressions if you need to use them:

gulpmath(5\;20); // returns [20]

Known Issues

Unit conversions work, but the results may produce unusual results:

gulpmath(5.08 cm to inch); // on Windows, this produces 2.0000000000000004 inch