68 lines
1.9 KiB
Markdown
68 lines
1.9 KiB
Markdown
Equation
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========
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Solve math expressions or create equations for repeated and complex Math tasks.
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To use in browser, download [`equation.min.js`](https://raw.githubusercontent.com/mdibaiee/Equation.js/master/equation.min.js).
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```javascript
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// solve
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console.log(Equation.solve('4 * lg(4) ^ 3')); // 32
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// equation
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let sphereArea = Equation.equation('4 * PI * r^2');
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console.log(sphereArea(5)); // 314.1592653589793
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```
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You can also register your own operators and constants.
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```javascript
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// these options are explained below
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Equation.registerOperator('$', {
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fn: a => 1/a,
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format: '10',
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precedence: 2
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});
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Equation.solve('$2'); // 0.5
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Equation.solve('$5'); // 0.2
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Equation.registerConstant('N', () => {
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return Math.random() * 10 + 10
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});
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Equation.solve('N'); // a number between 10 and 20
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```
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API
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===
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####solve(expression: String)
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Takes a math expression and evaluates it, returning the result.
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###equation(expression: String)
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Takes a math expression containing variables, returning a function which
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replaces the variables with given arguments, and solves the expression.
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###registerOperator(key: String, options: Object)
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Registers a new operator.
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Options:
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#####fn
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The function which runs on arguments
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#####format
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The format which specifies how arguments are placed relative to operator, this is a string in which 1 indicates operator and zeroes indicate arguments.
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For example `+` has the format `010` and factorial has `01`.
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#####precedence
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Specifies the precedence of operator. The less the value, the higher the precedence, resulting in soon execution.
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###registerConstant(key: String, value: Function/Number)
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Registers a new constant. value can be a function (takes no arguments), or a constant number.
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That's right, we have named these *constants* but they actually can change, that's why we can use functions to define them. An example is the `RAND` constant which calls `Math.random`.
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TODO
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====
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* Equation solver
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* More tests
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