In my nodejs(javascript) program, users are able to enter text and have it changed with a regular expression that they have inputted. I would also like the user to be able to enter text to be capitalized or lower-cased. If the user inputs the string "StackOverflow is great!", the regular expression (.), and sets it to be replaced by uppercase($1), the program should return "STACKOVERFLOW IS GREAT!" I can do this with:
var text = "StackOverflow is great!";
var regexp = new RegExp("(.)", "g");
var replaceWith = "uppercase($1)";
var uppercaseMatch = /uppercase\(([^)]+)\)/g.test(replaceWith);
var lowercaseMatch = /lowercase\(([^)]+)\)/g.test(replaceWith);
var result = text.replace(regexp, function() {
var argsCount = arguments.length;
if(uppercaseMatch) {
if(argsCount === 5) {
return arguments[1].toUpperCase() + arguments[2];
} else if (argsCount === 4) {
return arguments[1].toUpperCase();
}
} else if (lowercaseMatch) {
if(argsCount === 5) {
return arguments[1].tolowerCase() + arguments[2];
} else if (argsCount === 4) {
return arguments[1].tolowerCase();
}
} else {
if(argsCount === 5) {
return arguments[1] + arguments[2];
} else if (argsCount === 4) {
return arguments[1];
} else if (argsCount === 3) {
return replaceWith;
}
}
});
console.log(result);
It also works if they lowercase the string, and then it will return "stackoverflow is great!" This code will also run correctly if they do not enter any text to be uppercase or lowercase, such as [oO] as the regex and 0 as the replaceWith. However, it will not work with \b(\w) as the regex, and uppercase($1) as the replaceWith. I would also like this to work if a user wants to use multiple backreferences in replaceWith, such as a replace of ([aeiou]) and replaceWith $1$1. It should also be able to have more than one backreference, such as replacing ([a-zA-Z])([a-zA-Z]?) with uppercase($1)$2. Finally, I would like it to work when a user has both uppercase and lowercase in the replaceWith, like this: replace ([a-zA-Z']+,*)([.,?!\s]|)([a-zA-Z']+|) with uppercase($1)$2lowercase($3).
I can suggest something like this:
function fnReplace(regex, from, to) {
return from.replace(regex, function() {
var args = [].slice.call(arguments, 0);
return to.replace(/(\w+)\(\$(\d+)\)|\$(\d+)/g, function(_, fn, a1, a2) {
return fn ? args[a1][fn]() : args[a2];
});
});
}
Example:
s = fnReplace(
/(\w+) (\w+)/,
'hello THERE',
'toUpperCase($1) + toLowerCase($2) + $2 $1');
console.log(s) // HELLO + there + THERE hello
It allows arbitrary string functions in replacement:
s = fnReplace(
/(\w+) (\w+)/,
'hello THERE',
'bold($1) + sup($2)');
// <b>hello</b> + <sup>THERE</sup>
If this is not desired, change the inner regex to be like:
return to.replace(/(toUpperCase|toLowerCase|...)\(\$(\d+)\)|\$(\d+)/g, function(_, fn, a1, a2) {
return fn ? args[a1][fn]() : args[a2];
});
Related
I used the following code to extract initials and work fines, but it extracts last name initial as well.
String.prototype.getInitials = function(glue) {
if (typeof glue == "undefined") {
var glue = true;
}
var initials = this.replace(/[^a-zA-Z- ]/g, "").match(/\b\w/g);
if (glue) {
return initials.join('.');
}
return initials;
};
console.log("first middle last".getInitials());
How to remove last letter please?
Ignore the last index while joining. Also added some safety check using optional chaining so it doesn't return undefined.
String.prototype.getInitials = function(glue) {
if (typeof glue == "undefined") {
var glue = true;
}
var initials = this.replace(/[^a-zA-Z- ]/g, "").match(/\b\w/g)?.slice(0, -1) ?? [];
if (glue) {
return initials.join('.') ?? "";
}
return initials;
};
console.log("my name is".getInitials());
I have built this function to replace a group of characters in a string by a random value from another list within a function:
function replaceExpr(a) {
var expToReplace = 0
var newSent = a
while (expToReplace == 0) {
if (a.search("zx") == -1) {
expToReplace = 1
} else {
var startPos = a.search("zx");
startPos += 2;
var endPos = a.search("xz");
var b = a.substring(startPos, endPos);
var fn = window[b];
if (typeof fn === "function") var newWord = fn();
final = newSent.replace("zx" + b + "xz", newWord);
newSent = final
a = a.replace("zx" + b + "xz", "")
}
}
return final
}
function appearance() {
var list = [
"attractive",
"fit",
"handsome",
"plain",
"short",
"tall",
"skinny",
"well-built",
"unkempt",
"unattractive"
]
return list[Math.floor(Math.random() * list.length)];
}
function personality() {
var list = [
"aggresive",
"absent-minded",
"cautious",
"detached from the real world",
"easygoing",
"focused",
"honest",
"dishonest",
"polite",
"uncivilized"
]
return list[Math.floor(Math.random() * list.length)];
}
An example :
var a = replaceExpr("Theodor is a zxappearancexz man. He seems rather zxpersonalityxz.")
alert(a)
// Theodor is a unattractive man. He seems rather cautious.
Everything works perfectly with the function but I have an issue related to it. As you can see, there's one grammar mistake : it's written "a unattractive" where it should be "an unattractive".
There's a function I usually use to to fix the a\an issue which is :
var AvsAnSimple = (function (root) {
//by Eamon Nerbonne (from http://home.nerbonne.org/A-vs-An), Apache 2.0 license
// finds if a word needs a "a" or "an" before it
var dict = "2h.#2.a;i;&1.N;*4.a;e;i;o;/9.a;e;h1.o.i;l1./;n1.o.o;r1.e.s1./;01.8;12.1a;01.0;12.8;9;2.31.7;4.5.6.7.8.9.8a;0a.0;1;2;3;4;5;6;7;8;9;11; .22; .–.31; .42; .–.55; .,.h.k.m.62; .k.72; .–.82; .,.92; .–.8;<2.m1.d;o;=1.=1.E;#;A6;A1;A1.S;i1;r1;o.m1;a1;r1; .n1;d1;a1;l1;u1;c1.i1.a1.n;s1;t1;u1;r1;i1;a1;s.t1;h1;l1;e1;t1;e1.s;B2.h2.a1.i1;r1;a.á;o1.r1.d1. ;C3.a1.i1.s1.s.h4.a2.i1.s1;e.o1.i;l1.á;r1.o1.í;u2.i;r1.r1.a;o1.n1.g1.j;D7.a1.o1.q;i2.n1.a1.s;o1.t;u1.a1.l1.c;á1. ;ò;ù;ư;E7;U1;R.b1;o1;l1;i.m1;p1;e1;z.n1;a1;m.s1;p5.a1.c;e;h;o;r;u1.l1;o.w1;i.F11. ;,;.;/;0;1;2;3;4;5;6;71.0.8;9;Ae;B.C.D.F.I2.L.R.K.L.M.N.P.Q.R.S.T.B;C1;M.D;E2.C;I;F1;r.H;I3.A1;T.R1. ;U;J;L3.C;N;P;M;O1. ;P1;..R2.A1. ;S;S;T1;S.U2.,;.;X;Y1;V.c;f1.o.h;σ;G7.e1.r1.n1.e;h1.a3.e;i;o;i1.a1.n1.g;o2.f1. ;t1.t1. ;r1.i1.a;w1.a1.r1.r;ú;Hs. ;&;,;.2;A.I.1;2;3;5;7;B1;P.C;D;F;G;H1;I.I6;C.G.N.P.S1.D;T.K1.9;L;M1;..N;O2. ;V;P;R1;T.S1.F.T;V;e2.i1.r;r1.r1.n;o2.n6;d.e1.s;g.k.o2;l.r1;i1.f;v.u1.r;I3;I2;*.I.n1;d1;e1;p1;e1;n1;d2;e1;n1;c1;i.ê.s1;l1;a1;n1;d1;s.J1.i1.a1.o;Ly. ;,;.;1;2;3;4;8;A3. ;P;X;B;C;D;E2. ;D;F1;T.G;H1.D.I1.R;L;M;N;P;R;S1;m.T;U1. ;V1;C.W1.T;Z;^;a1.o1.i1.g;o1.c1.h1.a1;b.p;u1.s1.h1;o.ộ;M15. ;&;,;.1;A1;.1;S./;1;2;3;4;5;6;7;8;Ai;B.C.D.F.G.J.L.M.N.P.R.S.T.V.W.X.Y.Z.B1;S1;T.C;D;E3.P1;S.W;n;F;G;H;I4. ;5;6;T1;M.K;L;M;N;O1.U;P;Q;R;S;T1;R.U2. ;V;V;X;b1.u1.m;f;h;o2.D1.e.U1;..p1.3;s1.c;Ny. ;+;.1.E.4;7;8;:;A3.A1;F.I;S1.L;B;C;D;E3.A;H;S1. ;F1;U.G;H;I7.C.D1. ;K.L.N.O.S.K;L;M1;M.N2.R;T;P1.O1.V1./1.B;R2;J.T.S1;W.T1;L1.D.U1.S;V;W2.A;O1.H;X;Y3.C1.L;P;U;a1.s1.a1.n;t1.h;v;²;×;O5;N1;E.l1;v.n2;c1.e.e1.i;o1;p.u1;i.P1.h2.i1.a;o2.b2;i.o.i;Q1.i1.n1.g1.x;Rz. ;&;,;.1;J./;1;4;6;A3. ;.;F1;T.B1;R.C;D;E3. ;S1.P;U;F;G;H1.S;I2.A;C1. ;J;K;L1;P.M5;1.2.3.5.6.N;O2.H;T2;A.O.P;Q;R1;F.S4;,...?.T.T;U4;B.M.N.S.V;X;c;f1;M1...h2.A;B;ò;S11. ;&;,;.4.E;M;O;T1..3.B;D;M;1;3;4;5;6;8;9;A3. ;8;S2;E.I.B;C3.A1. ;R2.A.U.T;D;E6. ;5;C3;A.O.R.I1.F.O;U;F3;&.H.O1.S.G1;D.H3.2;3;L;I2. ;S1.O.K2.I.Y.L3;A2. ;.;I1. ;O.M3;A1. ;I.U1.R.N5.A.C3.A.B.C.E.F.O.O5. ;A1.I;E;S1;U.V;P7;A7;A.C.D.M.N.R.S.E1. ;I4;C.D.N.R.L1;O.O.U.Y.Q1. ;R;S1;W.T9.A1. ;C;D;F;I;L;M;S;V;U7.B.L.M.N.P.R.S.V;W1.R;X1.M;h1.i1.g1.a1.o;p1.i1.o1;n.t2.B;i1.c1.i;T4.a2.i2.g1.a.s1.c;v1.e1.s;e1.a1.m1.p;u1.i2.l;r;à;Um..1.N1..1.C;/1.1;11. .21.1;L1.T;M1.N;N4.C1.L;D2. .P.K;R1. .a;b2;a.i.d;g1.l;i1.g.l2;i.y.m;no. ;a1.n.b;c;d;e1;s.f;g;h;i2.d;n;j;k;l;m;n;o;p;q;r;s;t;u;v;w;p;r3;a.e.u1.k;s3. ;h;t1;r.t4.h;n;r;t;x;z;í;W2.P1.:4.A1.F;I2.B;N1.H.O1.V;R1.F1.C2.N.U.i1.k1.i1.E1.l1.i;X7;a.e.h.i.o.u.y.Y3.e1.t1.h;p;s;[5.A;E;I;a;e;_2._1.i;e;`3.a;e;i;a7; .m1;a1;r1. .n1;d2; .ě.p1;r1;t.r1;t1;í.u1;s1;s1;i1. .v1;u1;t.d3.a1.s1. ;e2.m1. ;r1. ;i2.c1.h1. ;e1.s1.e2.m;r;e8;c1;o1;n1;o1;m1;i1;a.e1;w.l1;i1;t1;e1;i.m1;p1;e1;z.n1;t1;e1;n1;d.s2;a1. .t4;a1; .e1; .i1;m1;a1;r.r1;u1.t.u1.p1. ;w.f3. ;M;y1.i;h9. ;,;.;C;a1.u1.t1;b.e2.i1.r1;a.r1.m1.a1.n;o4.m2.a1; .m;n8; .b.d.e3; .d.y.g.i.k.v.r1.s1. ;u1.r;r1. ;t1;t1;p1;:.i6;b1;n.e1;r.n2;f2;l1;u1;ê.o1;a.s1;t1;a1;l1;a.r1; .s1; .u.k1.u1. ;l3.c1.d;s1. ;v1.a;ma. ;,;R;b1.a.e1.i1.n;f;p;t1.a.u1.l1.t1.i1.c1.a1.m1.p1.i;×;n6. ;V;W;d1; .t;×;o8;c2;h1;o.u1;p.d1;d1;y.f1; .g1;g1;i.no. ;';,;/;a;b;c1.o;d;e2.i;r;f;g;i;l;m;n;o;r;s;t;u;w;y;z;–;r1;i1;g1;e.t1;r1.s;u1;i.r3. ;&;f;s9.,;?;R;f2.e.o.i1.c1.h;l1. ;p2.3;i1. ;r1.g;v3.a.e.i.t2.A;S;uc; ...b2.e;l;f.k2.a;i;m1;a1. .n3;a3; .n5.a;c;n;s;t;r1;y.e2; .i.i8.c2.o1.r1.p;u1.m;d1;i1.o;g1.n;l1.l;m1;o.n;s1.s;v1.o1;c.r5;a.e.i.l.o.s3. ;h;u1.r2;e.p3;a.e.i.t2.m;t;v.w1.a;xb. ;';,;.;8;b;k;l;m1;a.t;y1. ;y1.l;{1.a;|1.a;£1.8;À;Á;Ä;Å;Æ;É;Ò;Ó;Ö;Ü;à;á;æ;è;é1;t3.a;o;u;í;ö;ü1; .Ā;ā;ī;İ;Ō;ō;œ;Ω;α;ε;ω;ϵ;е;–2.e;i;ℓ;";
function fill(node) {
var kidCount = parseInt(dict, 36) || 0,
offset = kidCount && kidCount.toString(36).length;
node.article = dict[offset] == "." ? "a" : "an";
dict = dict.substr(1 + offset);
for (var i = 0; i < kidCount; i++) {
var kid = node[dict[0]] = {}
dict = dict.substr(1);
fill(kid);
}
}
fill(root);
return {
raw: root,
//Usage example: AvsAnSimple.query("example")
//example returns: "an"
query: function (word) {
var node = root, sI = 0, result, c;
do {
c = word[sI++];
} while ('"‘’“”$\''.indexOf(c) >= 0);//also terminates on end-of-string "undefined".
while (1) {
result = node.article || result;
node = node[c];
if (!node) return result;
c = word[sI++] || " ";
}
}
};
})({})
Now, the problem is that I can't find a way to use this function in conjunction with the replaceExpr. The following obviously wouldn't work because of order precedence :
var a = replaceExpr("Theodor is " + AvsAnSimple(zxappearancexz) + "man. He seems rather " + AvsAnSimple(zxpersonalityxz).")
I just recently started learning javascript so my knowledge is rather limited. Any ideas how I could overcome this?
Thank you!
You could use a regular expression to optionally match the " a " or "an" before your word in the input string and store that matched portion in a variable using the String.match() function, then check if that " a " or " an " exists in your matched string, do the manipulations you need to do and store that manipulated string in a separate variable, then use String.replace() to find that previously matched string again, and replace it wit
your manipulated string. The regular expression you could use for this is /(\san?\s)?(zx\w*zx)/gm
See the regular expression here for more context.
Thank you Joseph! With your help I managed to find something that works by using your regular expression. Here's my function :
function replaceExpr(a) {
var nbExprToReplace = 1;
while (nbExprToReplace == 1) {
if (a.search("zx") == -1) {
nbExprToReplace = 0;
} else {
var currentGroup = a.match(/(\san?\s)?(zx\w*xz)/);
var exprToChange = currentGroup[2];
exprToChange = exprToChange.slice(2,-2);
var exprToChange = window[exprToChange];
if (typeof exprToChange !== "function") {
alert("the keyword is not a recognized function!");
break;
} else {
exprToChange = exprToChange();
var final = exprToChange
};
if (currentGroup[1] === undefined) {
} else {
var newArticle = AvsAnSimple.query(exprToChange);
final = newArticle.concat(" " + final)
};
a = a.replace(currentGroup[0], " " + final);
};
};
return a;
};
Preface
I'm working on creating a Access Control String (or System) (ACS) string Parser/Interpreter with PEG.js. ACS strings are commonly used on Bulletin Board Systems (BBSs) to check access rights to particular areas of the board. For example, see Renegade's ACS documentation.
Example ACS Strings
Below are some simplified strings and their English translations for illustration:
// Has GM123 OR NOT GM456
GM123|!GM456
// Has GM123 OR NOT (GM456 AND GM789) (note: AND is implied in this grammar if not specified)
GM123|!(GM456GM789)
// Has GM123 AND NOT GM456 OR has GM789
GM123!GM456|GM789
// Has GM1 OR (NOT GM2 OR GM3)
GM1|(!GM2|GM3)
What I'm Trying to Achieve
What I would like to do here is parse and interpret (or "run") the ACS string and ultimately end up with a final boolean.
Grammar So Far
Below is the PEG.js grammer I've some up with so far. Note that the ACS strings themselves are a bit more complex than the examples above (I allow for example GM['abc','def']) but I think up to this point it's fairly self explanatory.
{
function checkAccessSingle(acsName, arg) {
return true;
}
function checkAccessMulti(acsName, args, anyMatch) {
return true;
}
function makeNot(not, x) {
return not ? !x : x;
}
}
start
= acsString
whitespaceChar
= ' '
ws
= whitespaceChar*
lineTerminatorChar
= [\r\n\u2028\u2029]
decimalDigit
= [0-9]
integer
= decimalDigit+ { return parseInt(text(), 10); }
asciiPrintableChar
= [ -~]
singleAsciiStringChar
= !("'") asciiPrintableChar { return text(); }
doubleAsciiStringChar
= !('"') asciiPrintableChar { return text(); }
nonEmptyStringLiteral
= "'" chars:singleAsciiStringChar+ "'" { return chars.join(''); }
/ '"' chars:doubleAsciiStringChar+ '"' { return chars.join(''); }
AND
= '&'
OR
= '|'
NOT
= '!'
acsName
= n:([A-Z][A-Z]) { return n.join(''); }
acsArg
= nonEmptyStringLiteral
/ integer
acsArgs
= first:acsArg rest:(ws ',' ws a:acsArg { return a; })* {
var args = [ first ];
for(var i = 0; i < rest.length; ++i) {
args.push(rest[i]);
}
return args;
}
singleAcsCheck
= not:NOT? n:acsName a:acsArg* {
return function() {
makeNot(not, checkAccessSingle(n, a));
}
}
/ not:NOT? n:acsName '[' a:acsArgs ']' {
return function() {
return makeNot(not, checkAccessMulti(n, a, false));
}
}
/ not:NOT? n:acsName '{' a:acsArgs '}' {
return function() {
return makeNot(not, checkAccessMulti(n, a, true));
}
}
multiAcsCheck
= singleAcsCheck+
acsString = multiAcsCheck
Where I Need Help
The main issue I'm having (if not others I haven't run into yet!) is handling precedence with () and the OR clauses. This may be something simple, but I've worked on this for days and have some up short. Again, what I'm ultimately attempting to achieve here is to feed in an ACS string and output a final boolean result. The various ACS "commands" (e.g. 'GM' in the above example) should make method calls that do the dirty work.
Here's a quick demo that parses your example input properly and shows how you could go about evaluating the expressions on the fly (which will return a boolean):
{
function check(name, value) {
// Dummy implementation: returns true when the name starts with 'A'
return name.charAt(0) == 'A';
}
}
start
= expr
expr
= or_expr
or_expr
= left:and_expr '|' right:expr { return left || right; }
/ and_expr
and_expr
= left:not_expr '&'? right:expr { return left && right; }
/ not_expr
not_expr
= '!' value:atom { return !value; }
/ atom
atom
= acs_check
/ '(' value:expr ')' { return value; }
acs_check
= n:name a:arg { return check(n, a); }
name
= c:([A-Z][A-Z]) { return c.join(''); }
arg
= c:[A-Z]+ { return c.join(''); }
/ d:[0-9]+ { return d.join(''); }
var fNum = parseFloat("32.23.45"); results in 32.23 but I need the string from last decimal point: 23.45
For example, the following strings should return the following values:
"12.234.43.234" -> 43.234,
"345.234.32.34" -> 32.34 and
"234.34.34.234w" -> 34.34
A fairly direct solution:
function toFloat(s) {
return parseFloat(s.match(/\d+(\.|$)/g).slice(-2).join('.'));
}
For example:
toFloat("32.23.45") // 23.45
toFloat("12.234.43.234") // 43.234
toFloat("345.234.32.34") // 32.34
toFloat("234.34.34.234w") // 34.34
Update: Here's an alternative version which will more effectively handle strings with non-digits mixed in.
function toFloat(s) {
return parseFloat(s.match(/.*(\.|^)(\d+\.\d+)(\.|$)/)[2]);
}
The following will do exactly what you would like (I'm presuming that the last one should return 34.234, not 34.24).
alert (convText("12.234.43.234"));
alert (convText("345.234.32.34"));
alert (convText("234.34.34.234w"));
function convText(text) {
var offset = text.length - 1;
var finished = false;
var result = '';
var nbrDecimals = 0;
while(!finished && offset > -1) {
if(!isNaN(text[offset]) || text[offset] === '.') {
if(text[offset] === '.') {
nbrDecimals++;
}
if(nbrDecimals > 1) {
finished = true;
} else {
result = text[offset] + result;
}
}
offset--;
}
return result;
}
Hi I am trying to trim string from both end in javascript but it not work properly.Script can't work or some times it lost focus from textbox.
I am write javascript like below & calling it in validate function
function trim(s)
{
if (typeof s!= "string") {
return s;
}
var retValue = s;
var ch = retValue.s(0, 1);
while (ch == " ")
{ retValue = retValue.substring(1, retValue.length);
ch = retValue.substring(0, 1);
}
ch = retValue.substring(retValue.length-1, retValue.length);
while (ch == " ")
{
retValue = retValue.substring(0, retValue.length-1);
ch = retValue.substring(retValue.length-1, retValue.length);
}
while (retValue.indexOf(" ") != -1)
{
retValue = retValue.substring(0, retValue.indexOf(" ")) + retValue.substring(retValue.indexOf(" ")+1, retValue.length);
}
return retValue;
}
function validate() {
// alert("Please! Enter Farm Name");
if (!trim(document.getElementById("<%=txtFarm_Name.ClientID%>").value)) {
alert("Please! Enter Farm Name");
document.getElementById("<%=txtFarm_Name.ClientID%>").focus();
return false;
}
}
I had written this function for trim, when the .trim() function was not available in JS way back in 2008. Some of the older browsers still do not support the .trim() function and i hope this function may help you.
TRIM FUNCTION
function trim(str)
{
var startpatt = /^\s/;
var endpatt = /\s$/;
while(str.search(startpatt) == 0)
str = str.substring(1, str.length);
while(str.search(endpatt) == str.length-1)
str = str.substring(0, str.length-1);
return str;
}
Explanation: The function trim() accept a string object and remove any starting and trailing whitespaces (spaces,tabs and newlines) and return the trimmed string. You can use this function to trim form inputs to ensure valid data to be sent.
The function can be called in the following manner as an example.
form.elements[i].value = trim(form.elements[i].value);
You could do some thing like the following
if(!String.prototype.trim) {
String.prototype.trim = function () {
return this.replace(/^\s+|\s+$/g,'');
};
}
Once the above code is executed it can be use like the following
var str = " Hello world ";
console.log(str.trim());
Or if jquery is being used in the project then something like the following will work too
var str = " Hello world ";
$.trim(str);