Typescript - How to convert the string ("console.log") to the function (console.log)

Question

Using typescript, I need to convert some strings like "Math.floor" and "console.log" to the functions Math.floor and console.log, in order to be able to use those functions when passed as a string parameter.

For example

applyFunction ("Math.floor", 4.2); // => Math.floor(4.2) => 4
applyFunction ("console.log", "Hi"); // => console.log("Hi") => Hi

And so on.

I tried adding them as keys and values in an object and scanning the object whenever needed. But since I don't have the time to continuously search for and add all existing Typescript functions, I'm looking for a more comprehensive approach.

nicholaswmin · Accepted Answer · 2017-06-12T14:17:43.737

3

FWIW you can use eval() to parse strings as code.

Example:

eval("console.log('foo')")

That being said, I'd advice you to be careful when using eval().

edited Jun 12 '17 at 14:17

answered Jun 12 '17 at 14:11

nicholaswmin

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For me it worked as: eval("console.log")('foo'); Thanx alot – TamerB Jun 12 '17 at 14:18

Fals · Answer 2 · 2017-06-12T14:17:25.290

1

If you are using the browser you can do:

window['Math']['floor'](4.2);
window['console']['log']('Hi');

Make sure you iterate over the namespaces, eval(string) works better.

edited Jun 12 '17 at 14:17

answered Jun 12 '17 at 14:13

Fals

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I've posted an answer below that uses `eval` but I like this one better – nicholaswmin Jun 12 '17 at 14:13
@NicholasKyriakides eval(string) does the work better, this one is just another approach it you are in the browser, but is difficult because you must iterate over namespaces – Fals Jun 12 '17 at 14:16
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why is it difficult, simple split and reduce – epascarello Jun 12 '17 at 14:17
eval('Math.floor')(4.2) was much easier for my situation. Thanks a lot – TamerB Jun 12 '17 at 14:21
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concerning espacarellos comment *"Math.floor".split(".").reduce((o,i)=>o[i],window)(5)* – Jonas Wilms Jun 12 '17 at 14:28

Typescript - How to convert the string ("console.log") to the function (console.log)

2 Answers2