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wizard04wsuwizard04wsu
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- convert to a module
- separate the tests from the code
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4 files changed

+178
-189
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4 files changed

+178
-189
lines changed

‎isType.js‎

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This file was deleted.

‎isType.mjs‎

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/**
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* A more robust 'typeof'.
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* https://github.com/wizard04wsu/javascript-type-testing
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*
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*
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* For each of the type testing methods, the only parameter is the item to be tested. These methods do not perform coercion.
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*
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* is(o) - Returns the item's type.
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* - NaN is considered its own type (instead of a number), since it essentially represents something that cannot be converted to a number.
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* - For objects, the type of the object is given instead of just 'object' (e.g., 'Array').
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*
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* is.defined(o)
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* is.undefined(o)
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* is.null(o)
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* is.nan(o) - NaN or a Number object with value NaN
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*
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* is.array(o)
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* is.bigint(o)
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* is.boolean(o)
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* is.date(o)
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* is.function(o)
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* is.number(o) - excludes NaN
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* is.number.infinite(o)
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* is.number.nan(o) - same as is.nan(o)
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* is.number.real(o)
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* is.regexp(o)
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* is.string(o)
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* is.symbol(o)
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*
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* is.object(o)
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* is.primitive(o)
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*
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*
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* is.noConflict() - Restores 'is' to what it was before this script replaced it.
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*/
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function is(o){
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if(o === void 0) return "undefined";
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const t = typeof o;
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if(t === "object"){
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if(o === null) return "null";
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let name = Object.prototype.toString.call(o).slice(8, -1);
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if(name === "Number" && 1*o !== 1*o) return "NaN";
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return name; //object type
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}
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if(o !== o) return "NaN";
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return t; //primitive type or "function"
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}
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function fn(type, eitherCase){
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if(eitherCase) return function (o){ return is(o).toLowerCase() === type; };
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return function (o){ return is(o) === type; };
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}
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is.undefined = function (o){ return o === void 0; };
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is.defined = function (o){ return o !== void 0; };
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is.null = function (o){ return o === null; };
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is.nan = fn("NaN"); //NaN or a Number object with value NaN
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//Note that JavaScript doesn't correctly treat all undefined forms as NaN (e.g., 1/0 and 0**0).
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is.array = fn("Array");
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is.bigint = fn("bigint");
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is.boolean = fn("boolean", true);
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is.date = fn("Date");
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is.function = fn("function");
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is.number = fn("number", true); //excludes NaN
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is.number.nan = is.nan;
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is.regexp = fn("RegExp");
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is.string = fn("string", true);
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is.symbol = fn("symbol");
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const infinity = 1/0; //Technically, 1/0 is an undefined form, but JavaScript treats it as Infinity.
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is.number.infinite = function (o){ return is.number(o) && Math.abs(o) === infinity; };
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is.number.real = function (o){ return is.number(o) && Math.abs(o) !== infinity; };
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is.object = function (o){ let t = typeof o; return (t === "object" && o !== null) || t === "function"; };
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is.primitive = function (o){ return !is.object(o); };
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export { is as default };

‎test/test.htm‎

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<html><head><title>isType test</title><script src="test.js" type="module"></script></head><body>
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View the console.
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</body></html>

‎test/test.js‎

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import is from "../isType.mjs";
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let i = 1,
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a = function (a,b){ console.assert(a === b, (i++)+". "+a+" !== "+b); };
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a(is(), "undefined");
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a(is(null), "null");
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a(is({}), "Object");
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a(is([]), "Array");
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a(is(arguments), "Arguments");
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if(window.BigInt) a(is(BigInt(5)), "bigint");
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else i++;
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a(is(false), "boolean");
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a(is(new Boolean()), "Boolean");
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a(is(new Date()), "Date");
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a(is(function(){}), "function");
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a(is(new Function()), "function");
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a(is(/a/), "RegExp");
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a(is(new RegExp("a")), "RegExp");
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a(is(""), "string");
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a(is(new String("")), "String");
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if(window.Symbol) a(is(Symbol()), "symbol");
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else i++;
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a(is(5), "number");
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a(is(new Number(5)), "Number");
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a(is(NaN), "NaN");
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a(is(new Number(NaN)), "NaN");
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a(is(1/0), "number");
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a(is(new Number(1/0)), "Number");
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a(is.defined(), false);
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a(is.defined(5), true);
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a(is.undefined(), true);
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a(is.undefined(5), false);
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a(is.null(null), true);
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a(is.null(5), false);
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a(is.array([]), true);
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a(is.array(5), false);
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a(is.array(arguments), false);
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if(window.BigInt) a(is.bigint(BigInt(5)), true);
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else i++;
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a(is.bigint(5), false);
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a(is.boolean(false), true);
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a(is.boolean(), false);
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a(is.boolean(5), false);
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a(is.date(new Date()), true);
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a(is.date(5), false);
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a(is.date(1*(new Date())), false);
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a(is.function(function(){}), true);
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a(is.function(new Function()), true);
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a(is.function(5), false);
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a(is.regexp(/a/), true);
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a(is.regexp(new RegExp("a")), true);
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a(is.regexp(5), false);
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a(is.string(""), true);
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a(is.string(new String()), true);
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a(is.string(5), false);
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if(window.Symbol) a(is.symbol(Symbol()), true);
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else i++;
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a(is.symbol(5), false);
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a(is.nan(NaN), true);
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a(is.nan(new Number(NaN)), true);
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a(is.nan(5), false);
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a(is.nan(new Number(5)), false);
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a(is.number(5), true);
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a(is.number(new Number()), true);
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a(is.number(NaN), false);
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a(is.number(new Number(NaN)), false);
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a(is.number(1/0), true);
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a(is.number(new Number(1/0)), true);
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a(is.number(""), false);
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a(is.number(new Date()), false);
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a(is.number(1*(new Date())), true);
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a(is.number.real(5), true);
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a(is.number.real(1/0), false);
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a(is.number.real(NaN), false);
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a(is.number.real("5"), false);
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a(is.number.infinite(1/0), true);
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a(is.number.infinite(5), false);
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a(is.number.infinite(NaN), false);
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a(is.number.infinite("Infinity"), false);
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a(is.object({}), true);
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a(is.object(5), false);
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a(is.object(new Number()), true);
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a(is.object(function(){}), true);
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a(is.primitive(), true);
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a(is.primitive(5), true);
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a(is.primitive(new Number()), false);
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a(is.primitive(NaN), true);
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a(is.primitive(new Number(NaN)), false);

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