How to use the isFunction function from underscore

Find comprehensive JavaScript underscore.isFunction code examples handpicked from public code repositorys.

underscore.isFunction is a function provided by the Underscore.js library that checks whether a given value is a function.

template-mixins.js

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};

// loop through mixins object and attach their handler methods
// to res.locals['mixin-name'].
_.each(mixins, function (mixin, name) {
  const handler = _.isFunction(mixin.handler) ? mixin.handler : function () {
    return function (key) {
      this.options = this.options || {};
      this.options.fields = this.options.fields || {};
      key = hoganRender(key, this);

crud.js

GitHub: GeraldWodni/kern.js

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    }
}, opts );
opts = _.extend( {
    readFields: function( req ) {
        var values = {};
        var fields = _.isFunction( opts.fields ) ? opts.fields( req ) : opts.fields;
        _.each( fields, function( fieldOpts, field ) {
            var source = fieldOpts.source || "postman";
            var filterName = fieldOpts.filter || opts.filters[ fieldOpts.type ] || field;

+ 11 other calls in file

How does underscore.isFunction work?

underscore.isFunction is a function provided by the Underscore.js library that checks whether a given value is a function. When you call underscore.isFunction, you provide a single input parameter. The function checks whether the input parameter is a function by checking its internal [[Class]] property, which is a string that represents the object's class. If the input parameter is a function, underscore.isFunction returns true. Otherwise, it returns false. By checking whether a value is a function, underscore.isFunction can be used to ensure that functions are only called with other functions as arguments, or to filter arrays or collections to only contain functions. This can be useful in a variety of JavaScript contexts, such as event handling, functional programming, and callback-based APIs.

leaflet-measure.js

GitHub: susanameono/Clase-9-correcta

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};

// Invoke a method (with arguments) on every item in a collection.
_.invoke = function(obj, method) {
  var args = slice.call(arguments, 2);
  var isFunc = _.isFunction(method);
  return _.map(obj, function(value) {
    return (isFunc ? method : value[method]).apply(value, args);
  });
};

+ 6 other calls in file

utils.js

GitHub: joneslee0918/Chat-Extend-Node

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 * If an object is thenable, then return the object itself, otherwise wrap it into a promise
 * @param {any}
 * @deferred
 */
when: function (param) {
  if (param != null && _.isFunction(param.then)) {
    return param;
    // eslint-disable-next-line no-undefined
  } else if (param !== undefined) {
    return new Promise(function(resolve) {

Ai Example

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const _ = require("underscore");

const items = [
  { id: 1, name: "Item 1", handleClick: () => console.log("Clicked item 1!") },
  { id: 2, name: "Item 2", handleClick: null },
  { id: 3, name: "Item 3", handleClick: () => console.log("Clicked item 3!") },
];

const clickableItems = _.filter(items, (item) => {
  return _.isFunction(item.handleClick);
});

console.log(clickableItems);

In this example, underscore.isFunction is used to filter an array of objects called items to only include those that have a handleClick property that is a function. The _.filter() function is used to iterate over each object in the array, returning only those objects that pass the filter function. When _.isFunction(item.handleClick) is called on each object, it returns true for the first and third objects, which have a handleClick property that is a function. The second object has a handleClick property that is null, so it is filtered out. The resulting clickableItems array contains only the first and third objects, which have functions for their handleClick properties. Note that underscore.isFunction can also be used in other contexts, such as validating input arguments to functions or checking whether a variable is a function before invoking it.

message-template-async.js

GitHub: joneslee0918/Chat-Extend-Node

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  // avoid undefined
  value = context.global.get(subtokens[1]) != null ? context.global.get(subtokens[1]) : null
} else if (token.startsWith('tx.')) {
  // use global translator
  const tx = context.global.get('tx');
  value = _.isFunction(tx) ? tx(token.replace('tx.', ''), language) : token;
} else if (specials[token] != null) {
  value = specials[token];
} else {
  // excluded global, payload, need to access to the context

classifier.js

GitHub: ArVinD-005/RepoA

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if (a == null || b == null) return a === b;
// Unwrap any wrapped objects.
if (a._chain) a = a._wrapped;
if (b._chain) b = b._wrapped;
// Invoke a custom `isEqual` method if one is provided.
if (a.isEqual && _.isFunction(a.isEqual)) return a.isEqual(b);
if (b.isEqual && _.isFunction(b.isEqual)) return b.isEqual(a);
// Compare `[[Class]]` names.
var className = toString.call(a);
if (className != toString.call(b)) return false;

+ 20 other calls in file

rest.js

GitHub: santlive/binanceimp

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    this._drift = 0;
    this._syncInterval = 0;
}

_makeRequest(query, callback, route, security, method, attempt = 0) {
    assert(_.isUndefined(callback) || _.isFunction(callback), 'callback must be a function or undefined');
    assert(_.isObject(query), 'query must be an object');

    let queryString;
    const type = _.last(route.split('/')),

aldeed_collection2-core.js

GitHub: NadeemBeg/shopSkip-liquor_app

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* @category Lang
* @param {*} value The value to check.
* @returns {boolean} Returns `true` if `value` is a function, else `false`.
* @example
*
* _.isFunction(_);
* // => true
*
* _.isFunction(/abc/);
* // => false

+ 13 other calls in file

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