JarCastingundefsafe
Simple function for retrieving deep object properties without getting "Cannot read property 'X' of undefined"
Can also be used to safely set deep values.
Usage
var object = {
a: {
b: {
c: 1,
d: [1,2,3],
e: 'remy'
}
}
};
console.log(undefsafe(object, 'a.b.e')); // "remy"
console.log(undefsafe(object, 'a.b.not.found')); // undefined
Demo: https://jsbin.com/eroqame/3/edit?js,console
Setting
var object = {
a: {
b: [1,2,3]
}
};
// modified object
var res = undefsafe(object, 'a.b.0', 10);
console.log(object); // { a: { b: [10, 2, 3] } }
console.log(res); // 1 - previous value
Star rules in paths
As of 1.2.0, undefsafe supports a * in the path if you want to search all of the properties (or array elements) for a particular element.
The function will only return a single result, either the 3rd argument validation value, or the first positive match. For example, the following github data:
const githubData = {
commits: [{
modified: [
"one",
"two"
]
}, /* ... */ ]
};
// first modified file found in the first commit
console.log(undefsafe(githubData, 'commits.*.modified.0'));
// returns `two` or undefined if not found
console.log(undefsafe(githubData, 'commits.*.modified.*', 'two'));