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Labs/Jetpack/JEP/11: Difference between revisions
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→Enumerating Specific Values: Added warning about check for null and strict equality
(→JEP 11 - Simple Persistent Storage: Updated authorship. Drew's done most of the work.) |
(→Enumerating Specific Values: Added warning about check for null and strict equality) |
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** <code>onResult(value)</code> is called for each key given in <code>keyArray</code>. If a given key does not exist in the store, <code>value</code> will be <code>undefined</code>. Values are enumerated in the same order that their keys are given in <code>keyArray</code>. | ** <code>onResult(value)</code> is called for each key given in <code>keyArray</code>. If a given key does not exist in the store, <code>value</code> will be <code>undefined</code>. Values are enumerated in the same order that their keys are given in <code>keyArray</code>. | ||
* <code>onResult(null)</code> | * <code>onResult(null)</code> | ||
** When all values are exhausted, <code>onResult(null)</code> is called to signal that enumeration is complete. | ** When all values are exhausted, <code>onResult(null)</code> is called to signal that enumeration is complete. Because <code>value</code> will be undefined when a given key does not exist, <code>onResult</code> should always use strict equality (<code>===</code> instead of <code>==</code> or <code>!value</code>) when checking for the <code>null</code> signal so that an <code>undefined</code> value is not mistaken for it. | ||
* <code>onError(errorMessage, keyArray)</code> | * <code>onError(errorMessage, keyArray)</code> | ||