toString() method

ECMAScript spec requires converting values to string, deep in the internals of the runtime (in particular, in a + b, a[b], a == b, etc.). It also mandates that these conversions use the .toString() method if provided on the object by the user.

These are complex to implement in very limited stack space available on embedded devices. Consider the following: .toString() triggers code execution with say property indexing, which triggers another .toString(), etc. See issue.

To alleviate this problem, the built-in string conversion for objects in DeviceScript is similar to util.inspect() in node.js - it will show a limited number of object fields. For example:

const o = { x: 1, y: ["foo", 2] }
console.log("o=", o)
console.log("o=" + o)
console.log(`o=${o}`)

Output

o={x:1,y:["foo",2]}
o={x:1,y:["foo",2]}
o={x:1,y:["foo",2]}