Develop Reference

Using regex to test out of 4 words in an array has a perfect match

I was tasked with a project of creating a CV site were the user uploads a .docx file and the details is extracted from the file and is automatically inputted in the template designed by me,
I have been able to extract the details .docx file with JavaScript and the extracted details was kept in an array to make it easy to identify words with indexing. For example
[Adeola Emmanuel, adeolaemmanuel#gmail.com, pharmacist, 2 ketu ikorodu lagos, etc].
where i need help is not all CV uploaded by the user has the name coming first or email coming second but its sure that they come within 0,6 of the array so i decided to write a function that will help with that but its not working
var email = email(text.slice(0, 5));
function email(email) {
var re = /.{1,}#[^.]{1,}/ig;
if (!re.test(email)) {
email = text.slice(0, 1);
return email;
} else if (re.test(email)) {
email = text.slice(3, 5);
return email;
}
}

You can use the find array method:
function getEmail(arr) {
let re = /\S#[^.\s]/;
return arr.find(str => re.test(str));
}
let text = ["Adeola Emmanuel", "adeolaemmanuel#gmail.com", "pharmacist", "2 ketu ikorodu lagos"];
let email = getEmail(text.slice(0, 5));
console.log(email);
Some remarks:
{1,} in regular expressions can be shortened to just +
You actually don't need to test for multiple occurrences with +, since you would already accept one occurrence. So that also means you would be OK with just one non-point character after the #.
Neither of the regex suffixes (ig) have any use in your regex.
The .test method should get a string as argument, not an array. So you need to pass it email[0] for example.
For a full test of whether some string is a valid email address, the regular expression would be way more complex
When an if condition is false, there is no need to test the exact opposite in the else block: by exclusion that opposite condition will always be true when it gets executed.
The slice of an array is still an array, so returning text.slice(3, 5); in the else block does not make sense. You want to return a string.
You need a loop to inspect other array elements for as long as you don't have a match and have not reached the end of the array. So some loop construct is needed. You can use for, while, or any of the array methods that do such looping. find is particular useful in this case.
Don't give your function the same name as another variable (email) as only one value can be assigned to that variable (a function, a string, or still something else). So in your case you'll lose the function definition by the var initialisation.

How to access the first two digits of a number

I want to access the first two digits of a number, and i have tried using substring, substr and slice but none of them work. It's throwing an error saying substring is not defined.
render() {
let trial123 = this.props.buildInfo["abc.version"];
var str = trial123.toString();
var strFirstThree = str.substring(0,3);
console.log(strFirstThree);
}
I have tried the above code
output of(above code)
trial123=19.0.0.1
I need only 19.0
How can i achieve this?

I would split it by dot and then take the first two elements:
const trial = "19.0.0.1"
console.log(trial.split(".").slice(0, 2).join("."))
// 19.0

You could just split and then join:
const [ first, second ] = trial123.split('.');
const result = [ first, second ].join('.');

I have added a code snippet of the work: (explanation comes after it, line by line).
function getFakePropValue(){
return Math.round(Math.random()) == 0 ? "19.0.0.1" : null;
}
let trial123 = getFakePropValue() || "";
//var str = trial123.toString();
// is the toString() really necessary? aren't you passing it along as a String already?
var strFirstThree = trial123.split('.');
//var strFirstThree = str.substring(0,3);
//I wouldn't use substring , what if the address 191.0.0.1 ?
if(strFirstThree.length >= 2)
console.log(strFirstThree.splice(0,2).join("."));
else
console.error("prop was empty");
Because you are using React, the props value was faked with the function getFakePropValue. The code inside is irrelevant, what I am doing is returning a String randomly, in case you have allowed in your React Component for the prop to be empty. This is to show how you an create minimal robust code to avoid having exceptions.
Moving on, the following is a safety net to make sure the variable trial123 always has a string value, even if it's "".
let trial123 = getFakePropValue() || "";
That means that if the function returns something like null , the boolean expression will execute the second apart, and return an empty string "" and that will be the value for trial123.
Moving on, the line where you convert to toString I have removed, I assume you are already getting the value in string format. Next.
var strFirstThree = trial123.split('.');
That creates an array where each position holds a part of the IP addrss. So 19.0.0.1 would become [19,0,0,1] that's thanks to the split by the delimiter . . Next.
if(strFirstThree.length >= 2)
console.log(strFirstThree.splice(0,2).join("."));
else
console.error("prop was empty");
This last piece of code uses the conditional if to make sure that my array has values before I try to splice it and join. The conditional is not to avoid an exception, since splice and join on empty arrays just returns an empty string. It's rather for you to be able to raise an error or something if needed. So if the array has values, I keep the first two positions with splice(0,2) and then join that array with a '.'. I recommend it more than the substr method you were going for because what if you get a number that's 191.0.0.1 then the substr would return the wrong string back, but with splice and join that would never happen.
Things to improve
I would strongly suggest using more human comprehensible variables (reflect their use in the code)
The right path for prop value checking is through Prop.Types, super easy to use, very helpful.
Happy coding!

Use window to execute a formula instead of using eval

My code need to execute a forumla (like Math.pow(1.05, mainObj.smallObj.count)).
My path is :
var path = mainObj.smallObj.count;
as you can see.
If needed, my code can split all variable names from this path and put it in an array to have something like :
var path = ["mainObj", "smallObj", "count"];
Since I don't want to use eval (this will cause memory leaks as it will be called many times every seconds), how can I access it from window?
Tried things like window["path"] or window.path.
If it is always unclear, let me know.
Thanks in advance for any help.
EDIT: forget to tell that some config are written in JSON, so when we take the formula, it's interpreted as "Math.pow(1.05, mainObj.smallObj.count)" so as a string.

I would say there are better solutions then eval, but it depends how the forumla can be structured. It could be precompiled using new Function (this is also some kind of eval) but allowing it to be called multiple times without the need to recompile for each invocation. If it is done right it should perform better then an eval.
You could do something like that:
var formula = {
code : 'Math.pow(1.05, mainObj.smallObj.count)',
params : ['mainObj']
}
var params = formula.params.slice(0);
params.push('return '+formula.code);
var compiledFormula = Function.apply(window, params);
//now the formula can be called multiple times
var result = compiledFormula({
smallObj: {
count: 2
}
});

You can get the path part reconciled by recursively using the bracket notation:
window.mainObj = { smallObj: { count: 2 } };
var path = ["mainObj", "smallObj", "count"];
var parse = function (obj, parts) {
var part = parts.splice(0, 1);
if (part.length === 0) return obj;
obj = obj[part[0]];
return parse(obj, parts);
};
var value = parse(window, path);
alert(value);
Basically, parse just pulls the first element off the array, uses the bracket notation to get that object, then runs it again with the newly shortened array. Once it's done, it just returns whatever the result of the last run is.
That answers the bulk of your question regarding paths. If you're trying to interpret the rest of the string, #t.niese's answer is as good as any other. The real problem is that you're trusting code from an external source to run in the context of your app, which can be a security risk.

CodeMirror - Using RegEx with overlay

I can't seem to find an example of anyone using RegEx matches to create an overlay in CodeMirror. The Moustaches example matching one thing at a time seems simple enough, but in the API, it says that the RegEx match returns the array of matches and I can't figure out what to do with it in the context of the structure in the moustaches example.
I have a regular expression which finds all the elements I need to highlight: I've tested it and it works.
Should I be loading up the array outside of the token function and then matching each one? Or is there a way to work with the array?
The other issue is that I want to apply different styling depending on the (biz|cms) option in the regex - one for 'biz' and another for 'cms'. There will be others but I'm trying to keep it simple.
This is as far as I have got. The comments show my confusion.
CodeMirror.defineMode("tbs", function(config, parserConfig) {
var tbsOverlay = {
token: function(stream, state) {
tbsArray = match("^<(biz|cms).([a-zA-Z0-9.]*)(\s)?(\/)?>");
if (tbsArray != null) {
for (i = 0; i < tbsArray.length; i++) {
var result = tbsArray[i];
//Do I need to stream.match each element now to get hold of each bit of text?
//Or is there some way to identify and tag all the matches?
}
}
//Obviously this bit won't work either now - even with regex
while (stream.next() != null && !stream.match("<biz.", false)) {}
return null;
}
};
return CodeMirror.overlayMode(CodeMirror.getMode(config, parserConfig.backdrop || "text/html"), tbsOverlay);
});

It returns the array as produced by RegExp.exec or String.prototype.match (see for example https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/String/match), so you probably don't want to iterate through it, but rather pick out specific elements the correspond to groups in your regexp (if (result[1] == "biz") ...)

Look at implementation of Code Mirror method match() and you'll see, that it processes method parameter for two types: string and RegExp.
Your constant in
stream.match("<biz.")
is of string type.
Define it in RegExp type:
tbsArray = /<biz./g
Thus, your stream will be matched with RegExp.

How to access key itself using javascript

I have a JSON like:
var xx = {'name':'alx','age':12};
Now I can read the value of name which is 'alx' as xx[0].name, but how should I retrieve value of 'name' itself? By that, I mean how can I fetch the key at run time?

for (i in xx) {
if (xx[i] == "alx") {
// i is the key
}
}

modified Code (from Victor) taking into account that you might want to look for any other possible string
var search_object = "string_to_look_for";
for (i in xx) {
if (xx[i] == search_object) {
// i is the key
alert(i+" is the key!!!"); // alert, to make clear which one
}
}

You are looking for associative arrays in Javascript. A quick google search suggests the following:
Read this page http://www.quirksmode.org/js/associative.html
and especially this section http://www.quirksmode.org/js/associative.html#link5